Forensic Scene Investigation
- Author: Renee M Robinson, MD; Chief Editor: J Scott Denton, MD more...
The autopsy begins before the decedent reaches the morgue; that is, analysis of the body at the scene is integral to death investigation, even before the first cut. Scene investigation is commonly (and mistakenly) assumed not to be an official component of the autopsy. Alan Moritz, MD, in his oft-cited journal article "Classical Mistakes in Forensic Pathology," addresses this assumption, and the possible adverse sequelae of pathologist absence at unclear or complicated death scenes. Correlation between bodily injury and all available evidence is crucial and best evaluated in the context of the death scene. The significance of certain findings "...may [only] be apparent to a medically trained person."
The importance of the pathologist at the scene has far-reaching implications beyond the investigation itself. In the comprehensive Forensic Pathology: Principles and Practice text, the authors reiterate that the presence of the pathologist helps establish a "...collegial working environment to facilitate optimal exchange of pertinent information" across several agencies.
A few comments are in order before proceeding further. Investigation into the circumstances of a person's demise does not always revolve around the subtext of salacious activity; not all suspicious or unusual deaths are the result of a crime. Herein, "crime scene investigation" shall be referred to as the more generic "death scene investigation."
For simplicity, the term "pathologist" or "investigator" will be used interchangeably when referring to the death scene investigator from either the coroner's or medical examiner's office. Also, "coroner" and "medical examiner" will be used interchangeably, although it is understood that there are often significant differences between coroner and medical examiner systems. It should be noted, however, that the make-up of a particular jurisdiction — its case volume, general population, geography, location, or availability of resources — may necessitate delegation of the investigator role to other appropriately trained professionals (ie, deputy scene investigators, nonpathologist medical doctors, police officers, etc).
History, Epidemiology, and Prevalence
Jurisdiction of death investigation is the responsibility of the local coroner or medical examiner. There is no uniform system across the United States; different states, counties, and cities use one or the other, or a hybrid of both. The differences between the 2 entities are not the focus of this article and will not be explicitly discussed.
Professional associations like the National Association of Medical Examiners (NAME) and the American Board of Medicolegal Death Investigators (ABMDI) are the most widely accepted resources for guidance regarding the general practice and certification of death scene investigators. However, there is also no officially mandated, transjurisdictional protocol for the investigation of a death scene. The National Medicolegal Review Panel (NMRP)* — a group consisting of medical, legal, and forensic professionals — sought to address this deficit and published Death Investigation: A Guide for the Scene Investigator (1999),whichsetforthacomprehensive protocol of suggested guidelines for investigators.
The motto of the NMRP is aptly, "Every Scene. Every Time."; that is, the scene should be approached systematically in each case so as not to omit crucial steps, but the overall intent of the guidelines is to provide a framework that can accommodate special or unexpected circumstances. There needs to be flexibility and even creative thinking when the investigation wanders outside the realm of the "norm."
* The NMRP was formed under the umbrella of the US Department of Justice (USDOJ), and in conjunction with The Centers for Disease Control and Prevention (CDC), the National Institute of Justice (NIJ), and the Bureau of Justice Assistance (BJA).
Overview of Scene Investigation
Topics regarding crime scene investigation — as it applies to the pathologist/investigator — will be addressed in this article. The goal of the pathologist/investigator at the crime scene differs from the duties of other scene officials. Some functions may overlap, however, and it is up to the pathologist/investigator to coordinate common efforts to optimize the overall investigation. The pathologist/investigator is charged with evaluating the decedent(s) in the context of known available medical, social, and environmental factors. The pathologist/investigator also serves to assist and guide involved officials based on those findings and objective interpretation. As a general rule, the scene "belongs" to the police, and the body "belongs" to the medical examiner or coroner.
Definitions and Terminology
Altered scene: An altered scene is a death scene in which the body has been moved, the microenvironment has been changed, or materials have been displaced or deposited before the arrival of the investigator.
Blood spatter: Blood spatter is generated when force is exerted such that it overcomes the surface tension of the parent blood source. Such forces can be due to several mechanisms such as impact (eg, gunshots, blunt force, or stabbing) or projection (eg, cast-off, arterial spray, or expiration). These forces generate shapes or patterns of blood on surfaces of variable size and shape and which are influenced by trajectory, force, surface properties, and environmental/situational factors (see the following images). (Also note: The correct term is "spatter," not "splatter"). See Blunt Force Trauma.
Cast-off: Cast-off is the bloodstain pattern created when a blood source is adherent to a moving object which is producing injuries (see the images below). When the objects is then moved and centrifugal forces become greater than the surface tension of the parent blood source, blood droplets with flight characteristics can strike nearby surfaces, often above, beside, or behind the assailant, in linear or curvilinear patterns. Examination of these bloodstain patterns may assist in the determination of the relative position of the assailant, with regard to the victim, at the time of injury.
Cause of death: Cause of death is defined as the underlying disease, injury, or poison which creates the anatomic or physiologic aberration that culminates in death. For example, a decedent's cause of death could be a "gunshot wound to the head." Depending on the scene and investigation, the manner of death could be suicide, homicide, or, rarely, accident.
Coroner: In some locales, a coroner is the individual charged with performing the death investigation and with taking jurisdiction over a body whose death is the result of a homicide, suicide, accident, or suspicious or ambiguous circumstances. A coroner is most often an elected official and is usually not required to be a forensic pathologist. In many jurisdictions, a coroner is not required to be a physician. A coroner may contract with a pathologist for the performance of autopsies.
Death scene: The death scene is the location where a person died or where the chain of events began that culminated in death.
Death scene investigator: The death scene investigator is the pathologist or medicolegal investigator charged with determining the circumstances around a death based on information gained from the context/location in which the decedent has been discovered. Both coroners and medical examiners work with death scene investigators to fulfill their mandates.
Manner of death: The manner of death is the classification of an individual's death based on the interpretation of the autopsy findings, scene investigation, and all available circumstantial data into one of the following categories: natural, accident, homicide, suicide, or undetermined. ("Pending" may also be used if additional studies are in progress; some jurisdictions also have "therapeutic misadventure" as an option).
Medical examiner: A medical examiner is an individual charged with performing the death investigation and taking jurisdiction over a body whose death is the result of a homicide, suicide, accident, or suspicious or ambiguous circumstances. A medical examiner is usually an appointed official, required to be a physician, and is a forensic pathologist.
Personal protective equipment: The category of personal protective equipment (PPE) includes the gowns, masks, shoe covers, gloves, hair covers, or other materials used by medical professionals to minimize personal exposure to environmental pathogens.
Primary scene: A primary scene is the location where the lethal injury or toxicity actually occurred.
Secondary scene: A secondary scene is the location to which the body had been moved before the body was found. This may also be referred to as a "dump site."
The coroner or medical examiner generally has jurisdiction over a body in which the decedent's manner of death is considered to be any of the following:
Suspicious or unexpected: These may include, but are not limited to, deaths within a 24-hour period of hospital admission, infant deaths, deaths in which the person has not been under the recent care of a physician, and deaths in a "previously healthy person."
Homicide: This is traditionally defined as any death occurring at the hand of another, either by act or omission.
Suicide: This category includes any death that involves the intentional taking of one's own life.
Accident: Accidental deaths are those occurring as a result of unintended circumstances and/or outcomes.
In addition, the medical examiner may also be called up to investigate natural deaths, which occur as the result of the natural progression of disease. This may not be intuitive to lay persons, but in many instances, an initially suspicious scene or findings may, in fact, be the result of a natural death (eg, massive hemoptysis, "purging" due to decomposition following a heart attack. See the section on " Common Misconceptions.") Due to epidemiologic and public health concerns, deaths from potentially infectious agents or a suspected public health problem may also fall under the jurisdiction of the coroner or medical examiner.
Manner of death
In forensic practice, the manner of death is determined by considering the primary insult that eventually leads to death. For example, John Doe was the victim of a robbery in 1979. He suffered a gunshot wound to the spinal cord, rendering him a paraplegic, but he ultimately survived. For the next 30 years, Mr. Doe was confined to a wheelchair. In the later years of his life, he developed decubitus ulcers, abscesses, and overwhelming sepsis as a result of his immobility, and died. The manner of death would be certified as a "homicide," as the initial insult (the gunshot wound to the spinal cord) set off a chain of events (paraplegia, immobility, ulcers, sepsis) that led to a compromise in his health status, and ultimately his death. Thus, seemingly "natural" deaths may, in fact, fall under medical examiner/coroner jurisdiction if a thorough investigation is carried out.
If a case falls under the jurisdiction of the coroner/medical examiner, at a minimum the investigator should be provided with a description of the scene and the circumstances surrounding death from a responding official. Optimally, scene investigation should be carried out by the pathologist or trained investigator in homicides, unexpected infant fatalities, and in other suspicious deaths.
Checklist for Scene Investigation
It is suggested that a "scene bag" include a number of items designed to protect the investigator (eg, personal protective equipment [PPE], all-weather clothing, disinfectant), preserve the integrity of the scene and body (body bags, crime scene tape, shoe covers, etc.) and provide the tools needed to perform a complete scene investigation and evaluation of the body (camera, evidence containers, thermometer, etc).
This section will discuss arriving at the scene, before entering the scene, and working and leaving the scene.
Arriving at the scene
Although the pathologist responding to the scene has jurisdiction over the body, the law enforcement agency is responsible for processing the scene and protecting its integrity. The 2 entities must interact efficiently and effectively, beginning with the arrival of the pathologist. This process begins with mutual respect for the other's role in the investigative process.
The following are suggested guidelines for the investigator in his/her initial approach to the scene.
Park within the appropriate designated area (for safety and security). 
Document arrival time and date.
Present identification at the checkpoint.
Identify and make initial contact with the lead investigator or police officer and additional appropriate officials. State the purpose and intent of the investigator's presence at the scene. 
Before entering the scene
Scene briefing should ideally occur before the investigator's entrance. Discussion of pertinent facts with officials, first responders, and eyewitnesses (if appropriate) should be undertaken, avoiding extraneous information in order to maintain objectivity. The following should be identified, if possible:
Who: Preliminary identification of the decedent(s) and their relationship to other living parties at the scene, if applicable.
What: The officials will explain the purported nature of the death, "We think this death is warrants coroner/medical examiner [ME] involvement, because (the person was previously healthy; the person has a gunshot wound to the back of the head; etc)."
Where: This includes a description of the general location in the jurisdiction (south side of the city, etc), the address (if available), and the environment (inside the decedent's house, in a neighbor's garage, etc). It is important to document identifying location markers. Photos of the mailbox or address imprint, nearest street sign, sign displaying the building name, or other landmarks will help establish exact location for future reference.
When: Investigators may be able to narrow down the window period in which a person has died (for instance, the suspect was seen running away from the decedent's home after gunshots were heard at 1:00 AM) by asking the right questions. This is not always the case, but it is still possible to use contextual clues to help determine approximate time of death, such as  : (1) dates of magazines/newspapers, mail, personal calendars in close proximity; (2) recent change(s) in the decedent's habits (eg, neighbors note that Mr. Smith took a walk every morning, but he hasn’t been seen for 3 days, and he is now in his home moderately decomposed; and (3)decomposition changes. (See " Postmortem Changes.")
(And, possibly) Why: When appropriate, known information/supposition should be included into the preliminary assessment whilst remaining objective (Investigators: "We think this person committed suicide because of this note/because they called a friend and said as much/because they were recently indicted/filed for bankruptcy/getting a divorce/under the treatment of a physician for a severe mental illness/etc"). It may be useful to include a statement at the end of the scene report to indicate that "the aforementioned conclusions are subject to revision due to ongoing investigation."
Verification of scene safety and permission to enter and take photographs should be obtained before scene entry. Law enforcement officials should be able to determine hazards before the investigator's arrival. Possible dangers may include the following:
Dogs or menacing animals/menacing people
Methamphetamine or other illicit laboratories
Chemicals, bomb-building materials
Biohazards (sharp objects, etc), biologic issues (toxic smells, toxic plants, animals, naturally occurring substances)
Barrier hazards (a precarious location/unstable building, etc). Use PPE, if necessary.
Cognizance of appropriate entrance and exit points helps prevent further disruption of the scene and evidence and minimizes introduction of non – scene-related artifacts.
Working the scene
Above all, it is important that cooperation between the ME's office and law enforcement is maintained, and that local and federal laws are followed.
To begin, it is important to identify designated scene parameters in conference with law enforcement officials (ie, the area roped off with scene tape). Discussion with scene personnel, based on the investigator's preliminary observations and interpretations, can help determine whether or not the area needs to be expanded or otherwise adjusted. Consensus should be reached and coordination of any changes should be undertaken in conjunction with law enforcement.
In addition, avoid making a beeline to the body. Most investigators believe systematic evaluation of the scene should begin at the periphery, gathering facts, taking photographs, making observations, and preserving objectivity before analysis of the body. The spiral circle (outward in) and grid methods are commonly used.
Photographic documentation of the scene may include both taking pictures from points of reference in an overlapping, 180 º manner and documenting the location of the body using different angles and piecemeal-approach photographs. (This provides a field of view and frame of reference for closer photographs.)
Case 1: Using surrounding scene objects to determine potential reasons behind a death
A decedent was found unresponsive in his home. Preliminary search of his domicile revealed an unkempt living environment with scattered trash, disorganized furniture and household items, and several clues to the decedent's lifestyle (see the image below).
Leaving the scene
Optimally, at the conclusion of the scene investigation, the investigator should be able to suggest a preliminary cause and manner of death, thus allowing law enforcement officials to accurately streamline their investigation. In some cases, it may be possible for the pathologist to suggest a type of weapon which may have inflicted a specific injury.
At the conclusion of the investigation, contact information for the investigating officer should be confirmed. If known, a general time (or date) for the autopsy may be of interest to participating officials. The scene exit should be by the same route as entered, unless instructed otherwise.
Gross Examination and Findings/Trace Evidence
In this section, several important issues the investigator takes into account and/or note of at a scene investigation are discussed.
Active weaponry may be present.
The investigator, upon approaching the body, should be cognizant of active weaponry on the body (eg, handguns) that should be secured and removed by appropriate officials before examination. It is necessary to photographically document any weapon(s) found if they are secure and available.
The death of the individual should be confirmed.
This may seem obvious, but it is nonetheless a logical step. Assessment may include: checking the "pulse, respiratory rate, and reflexes as appropriate." Other appropriate person(s) may have also confirmed and pronounced death.
The body may be located in a public area or noticeable to outside observers/onlookers.
If this is the case, the decedent should be shielded during the examination, especially if it is necessary to remove clothing from the body. Some methods to assist in privacy include the following:
Move vehicles to block line of sight or create additional barriers.
Use draped sheets, tarps, or other barriers.
In rare instances, the body itself may need to be moved. Preservation of evidence must be evaluated in the context of the scene, and the need for body removal must supersede the reasons for not removing the body.
Where the body is found and examined isn’t always where the person died.
The location of death should be established to the best of the investigator's ability. Examination of the body may reveal findings inconsistent with the current location or position of body. Some injured individuals may have travel a few feet or even several blocks after the initial fatal insult. Evaluation of livor, rigor, drag marks, and general positioning of the body may reveal that the decedent had been moved after death. These findings can be correlated with the police and witness report(s).
Environmental issues may be a concern when multiple bodies are present.
Scenes involving multiple bodies may be a clue as to a possible environmental issue (eg, carbon monoxide poisoning or oxygen displacement). It is important to confirm that the scene is safe to explore if this is suspected. There may be discrepancies in the decomposition rate among multiple decedents. Photography and documentation of these discrepancies and assessment of the relationship of one body to another will assist the investigator and/or autopsy pathologist in determining the role the environment may have played deaths of the individuals.
A systematic evaluation is important.
A good rule of thumb for systematic evaluation is "clothing before removal, skin before washing." Always work outside-inward. The detailed external examination of the body begins by describing and documenting (written and photographic documentation) the personal effects on the body, including the following:
Documentation and description of the decedent's type of clothing (work, nightwear, etc), or lack of clothing
Documentation of the presence of drugs (illicit, prescription, over-the-counter) and related paraphernalia (eg, straws, syringes). Note that sharp objects or other potentially infectious or harmful substances may be pocketed. Initially patting the pockets from the outside, inverting the pockets with long forceps, or using other "hands-off" techniques is preferred over reaching into blind areas.
Documentation of the presence of money (how much, what type)
Documentation of the presence of personal valuables (jewelry)
Documentation of the presence of identification [ID] (driver's license, passport, work ID). Personal ID and personal effects are usually laid out, either at the scene or at the time of autopsy, and photographed. If potential evidentiary items are removed at the scene, these are photographed and immediately receipted to the police jurisdiction in order to preserve the "chain of evidence." In most circumstances, the clothing is left on at the scene; if removal is warranted, steps should be taken to minimize disruption.
Assessment of body temperature. This may be through physical contact or taken via the external auditory meatus, axillary, or another acceptable method. Oral, anal, or percutaneous incision sites should be avoided as these processes can destroy potential evidence and introduce artifacts.  Note that in cases in which body temperature may be critical (eg, "excited delirium," hyperthermia or neuroleptic malignant syndrome), a photograph of the temperature reading with a wristwatch or camera time stamp places this datum point in context with the scene.
Systematic documentation and photography of obvious injuries is imperative.
This may be performed by medical examiner/coroner personnel or police agencies, depending on local practice. One approach involves beginning with the feet, moving up to the head on the left side, evaluating the head, then moving down the right side of the body down to the feet again. (The back of the body should be approached in the same method). Pertinent positive as well as negative findings should be documented along the way (measurements and locations of injuries or other important findings), using a scale within the photograph as appropriate.
In particularly violent deaths, the decedent may not be intact; all pieces of the body present at the scene should be documented as to position before collection.
The following baseline photographs may be taken: close-range photographs of the palmar and dorsal surfaces of both of the hands with documentation of any evidentiary subject matter (ie, blood spatter, visible gunshot residue, or defense-type injuries), and straight-on, oblique, and profile photographs of the face for potential identification purposes. Other adjunct photos may include scars, remote injuries, tattoos and piercings, medical intervention, and medical devices.
Consistent photography methods for each case helps reduce oversight and permit greater flexibility, if the scene dynamics demand it.
Based on the circumstances of the death, a directed, site-specific evaluation may be necessary (ie, conjunctival petechiae in hangings, fingernails in a struggle, naso-oral secretions in an overdose or drowning scenario).
It is important to document and photograph possible implements that may morphologically correlate to injury patterns on the body (ie, patterned rope used in a hanging that matches the pattern around the neck; a baseball bat nearby in a scene involving a decedent with extensive patterned abrasions and/or "tramline" or "tram-track" contusions.
Based on the decedent's injuries, the scene may need to be reevaluated or require additional photographs.
For example, if a decedent has been shot, and an anterior and posterior bullet wound has been identified, law enforcement officials can then be directed to the possible scene location of an exited bullet. (Note: An absolute determination of exit and entrance wounds may not be prudent at the scene. See the section on Common Misperceptions.)
Physical findings are not always of the criminal variety. For example, in a decedent with clubbed fingernails or a barrel chest, document the nightstand with an overflowing ashtray; abdominal ascites and diffuse jaundice may lead to the discovery of a number of hidden alcohol bottles; antecubital markings, abrasions, punctures, or ecchymoses may lead to the discovery of syringes and other illicit paraphernalia.
In the last example, the decedent's prescription drugs or illicit drugs should be noted, including the quantity prescribed and the quantity remaining. This information can provide insight into the decedent's past medical history, the name of an attending physician for later consultation, and, depending on the type and amount of medicament(s) remaining, may provide potential clues as to the cause and even the manner of death.
Document postmortem changes or artifacts.
Familiarity with common decomposition changes helps avoid misinterpretation. Sanguineous "purging" from the nose, mouth, ears, vagina, or anus; abdominal bloating; skin slippage; postmortem drying artifacts on the skin or sclera; insect or animal activity; and other changes can not only severely distort the decedent's "normal" physical profile but may also make a benign scene appear suspicious for the unindoctrinated. (See Postmortem Changes.)
Some common artifacts described by Moritz, in addition to the ones above, include the following :
Vessication: This process involves formation of dermal blebs/vesicles that can resemble blisters from burns.
Nonuniform decomposition: This may occur if one part of the body is exposed to different temperatures/environmental conditions than other parts, such as light from a window.
Abnormal rectal or vaginal distention: Such changes may occur in the absence of penetrative trauma and is a normal postmortem change.
Heat fractures: Decedents involved in fires or exposed to high temperatures demonstrate skeletal fractures not indicative of antemortem injury.
Thermal "hemorrhage": Coagulation and pooling/accumulation of blood due to heat, especially over the dura, may mimic antemortem hemorrhaging.
Changes to the scene as a result of decomposition can occur as well. Fluids may seep or leak from orifices ("purging") after death. The process of decomposition involves cellular breakdown and microbial activity that produces gases within the body, creating bloating. These gases, under pressure, may erupt, causing tissue and other bodily fluids to spatter in a manner that can mimic violent activity. Likewise, insect activity can cause artifacts: engorged insects may drag their exoskeletal thorax across the room, leaving a trail of bodily fluids behind, resembling classic blood spatter patterns. These natural occurences should not be attributed to foul play. (See Postmortem Changes.)
Case 2: Postmortem artifacts
The following image represent 3 separate cases that were initially confusing to primary scene responders.
The image below is that of a decedent found in his home surrounded by copious, dark red fluid thought to be blood. This scene was initially called suspicious, but upon examination, it was noted that the decedent had, in fact, been dead for several days and was decomposing (note the marbling of the skin of the forearms). There was no sign of external trauma. The sanguineous fluid had been purged and was not the result of trauma.
The following figure is of a decedent found in his bedroom with massive blood loss. Police were initially suspicious of foul play. Cursory examination at the scene did not indicate any severe external trauma. The decedent had a history of excessive alcohol use. At autopsy, it was discovered the blood loss was from an upper gastrointestinal source.
The decedent in the image below was discovered as is. Unfamiliar law enforcement officials were initially concerned that the decedent was "being attacked" at the time of death, hence the "defensive posturing." The decedent had, in fact, died in another location and had been moved postmortem, after full rigor had set in. Note the livor with dependent blanching on the right forearm and left palm.
Medical intervention, including artifacts, should be documented and photographed.
Mechanical intervention includes cardiopulmonary resuscitation (CPR), which can introduce a number of injuries including external chest contusions, sternal fractures, rib fractures, or, rarely, liver injury.
Procedural intervention includes the following:
Endotracheal placement or tracheotomy/cricoidotomy
Emergent thoracotomy or chest tube placement
Nasogastric tube placement
Central line placement
Once the scene and body have been thoroughly evaluated, a "final check" should be performed.
A final check may involve the following:
Appropriate collection of the body to help preserve trace evidence. Paper bags tied with string or affixed with rubber bands on the hands (and feet, if warranted) preserves evidence on the skin or under the fingernails/toenails. The body should be carefully placed in an appropriate bag and transported to the morgue.
Wrap up loose ends with law enforcement or other scene officials, including exchange of contact information for optimal coordination.
Unless instructed otherwise by officials on the scene, adopt the trail hiker's approach of "Pack out what is packed in." "Trash" accumulated at the scene as a byproduct of the investigator's examination should not be discarded but instead collected and disposed of (as appropriate) off-site. The idea is to minimize trace evidence (including hairs, fluids, and nucleic acids) introduced by investigating personnel at a scene. Exiting through the appropriate exit also assists in this goal.
Document the time the investigator leaves the scene.
Quite often, all the information one needs to complete the death investigation is at the scene, with the body in place in the context of death.
In fact, the majority of the time, the probable cause and manner of death should be established before leaving a death scene, and the autopsy is an adjunct for collecting evidence (if any) and confirming what was already surmised from the investigation. Unless there is simply no information to be had, it is important that the investigator has had their questions answered to their satisfaction; additional time at the scene may be needed to observe, examine, or investigate. Even despite investigator thoroughness, a return to the scene at a later time to gather more information may be necessary.
Case 3: Returning to the scene
A partially decomposed, partially eviscerated, white male was found in a remote area of New Mexico, near his home. The decedent had not been heard from for a 48-hour period. Friends, concerned about his well-being, visited his residence and found the decedent. A cougar was seen in the vicinity, circling the small area where the decedent was found. An attempt by fish and game wardens to kill the cougar using a shotgun was unsuccessful, and the wounded cougar escaped. Additional scene evaluation revealed drag marks leading to the body, with scattered tissue and clothing along the way.
Bodily injuries included skin and soft-tissue degloving, partial evisceration, fractures, slitlike skin lacerations, punctuate wounds on the extremities, and abrasions. (See the images below.) Gross and histologic analyses revealed a vital tissue reaction, consistent with an antemortem reaction to injury.
Circumstantial witness reports and the extent of injuries indicated a possible cougar attack. A return to the scene was warranted to collect further evidence and apprehension of the cougar by local officials, if possible.
The cougar was found near the vicinity of the residence and was snared and shot. Evaluation of the cougar revealed retained shotgun pellets and wounding patterns consistent with ammunition that was fired at the cougar seen in the vicinity at the time the body was discovered. Further evaluation of the cougar's canine teeth with respect to the wound patterns on the body revealed an equidistant intercanine pattern (see the following image). Research into general cougar behavior revealed that cougars are "reluctant scavengers," and that circling a recently killed prey is an act of territorial marking.
Given the evidence provided by the scene, the autopsy findings, and the apprehension and examination of the "perpetrator," the manner of death was certified as accident.
Special Dissections/Autopsy Procedures
Special procedure are generally not undertaken at the scene per se. Invasive techniques are discouraged, as they obfuscate potential evidence and may induce artifacts. Collection of bodily fluids (if not impermanent), extensive wound evaluation, and some trace evidence collection is best deferred to the autopsy, in the controlled, well-lighted, and well-equipped environment of the morgue.
Photography and Documentation
After establishing that it is permissible to take photographs, pictures of the scene should be obtained before taking pictures of the body. A wide-angle shot may be an appropriate first step; some investigators will use the "3-corners" method, whereby the investigator stands in 1 corner of the room and attempts to capture the other 3 corners in the photo. This may not always be feasible, therefore choosing the best vantage point becomes important. For example, if the scene involves someone falling or jumping from a certain height or down a flight of stairs, be sure to photographically document both the vantage point from that height, looking down, as well as the vantage point looking upward from the point where the body came to rest (point of fall/jump to point of landing).
Different angles may help to tell the story with the photographs. Materials introduced to the scene (eg, the investigator's bag) and living people (eg, police officers) should be excluded from the photographs if at all possible. Some photographs may benefit from the use of a scale. It is worth noting that in many jurisdictions all photos are evidence, even bad ones or ones shot out of focus, so none should be discarded or deleted.
Fragile or evanescent evidence should have a photo taken as soon as possible and then be preserved in an appropriate transport container/medium with proper labels. If trace evidence is seen on the body, it may be prudent to allow the police to collect this directly so they can initiate the chain of custody. Moritz created a list of common mistakes when collecting evidence during the autopsy, but much of it can apply to collection at the scene as well. These errors include the following :
Use of unclean containers
Contamination of specimens by reusing the same tools
Permitting blood/tissue to putrefy by inappropriate transportation and storage
Inadequate sampling or poorly selected samples
Lack of chain of custody
In addition to photography, alternative documentation of the death scene may prove useful. This adjunctive documentation may include: (1) sketches or hand drawings of the scene, noting pertinent landmarks for future reference; and (2) descriptions, in words, of the temporal relations between objects and the body; of any additional findings and evidence (eg, blood spatter, patterns); and of the qualities of the environment (odors, degree of lighting, terrain, temperature) See the following images from a case.
Ancillary and Adjunctive Studies
The above discussed template for scene investigation is designed to be vague enough to encompass a wide variety of circumstances. It cannot be stressed enough that modification of the general protocol is at the discretion of the investigator, pathologist, or office and must be tailored to the specifics of the case. That being said, there is a subtype of death investigation that deserves a separate structured review.
Investigating the death of an infant
Investigating an infant death may present additional challenges and questions beyond those of an adult death scene investigation.
In 1993, a workshop created with the Centers for Disease Control and Prevention (CDC), the National Institute for Child Health and Human Development (NICHD), and the National Institutes of Health (NIH) sought to "establish a standard protocol" for sudden, unexplained infant deaths (SUID) and sudden infant death syndrome (SIDS) deaths. The result was the creation of the Sudden Unexplained Infant Death Investigation Reporting Form (SUIDIRF), a document designed to address the pertinent and requisite protocols for processing a death scene investigation involving an infant. The form should be used at least as a reference in all appropriate cases and can be adopted and modified by any jurisdiction. It is considered to be an adjunct to individual jurisdictions' standardized protocols.
The definition of SUID is: "Those deaths for which no cause of death was obvious when the infant died."
Fatalities classified as SIDS fall under the umbrella of SUID, and are defined as: "The sudden death of an infant under one year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history."
To illustrate, an infant death may be a SUID—sudden, (initially) unexplained—but after investigation, the death is determined to be "suffocation due to plush bedding." The death is not considered a SIDS death, as there was an explanation. SIDS is a classification term that is used when the cause of death cannot be determined—it is not a diagnosis.
It should be noted that information with respect to the points below may not be known at the time of the scene investigation but should be followed up, either by the investigator or pathologist responsible for the case. Investigation into SUIDs will be further detailed in a separate article, Pediatric Deaths.
The SUIDIRF roughly divides the investigation into investigation data, witness interview, infant medical history, pregnancy history, incident scene investigation, scene diagram/body investigation diagram, and final summary. Additional information added here and not explicitly included in the SUDIRF is cited throughout.
These include basic information (time, date, address, etc), infant demographics, and caretaker demographics.
The witness interview consists of events in last 24-72 hours, with a description of the events leading up to and including the discovery of an unresponsive infant, subsequent medical intervention, and emergency service response.
Infant medical history
Pre-, peri-, and postnatal issues and/or complications, congenital abnormalities, and newborn screening should be elicited, as well as the status of current siblings (living or deceased, healthy or unhealthy), or the history of other close-proximity, nonrelated infant health issues or deaths; and the infant dietary history (who feeds the infant, what is the infant fed, how is the infant fed, time and quantity of last feeding).
Collect information about the status of birth mother (living or deceased, healthy or ill, determining who is primary caretaker). Did the mother receive prenatal care?
Incident scene investigation
The following information should be evaluated:
Home or other site
Ratio of children-to-adults present at time of death
Condition of environment (ie, environmental toxins, cigarettes/drugs/alcohol, cleanliness, presence of food in refrigerator) 
Relation of the body to the environment (presence of bedding materials, crib location and positioning, co-sleeping, heaters or air conditioners, etc)
Scene diagram/body investigation diagram
Draw a diagram of the floor layout, noting the body with respect to the surrounding environment.
Include body diagrams (front and back), with a description of the external examination (similar to adults death investigations, with additional considerations), noting the following:
Positioning and livor; cleanliness (nails, hair, feet) 
Type and cleanliness of clothing and environmental appropriateness
Note: If the infant has been moved for medical intervention, a doll may be used as a stand-in for the scene investigation and photos, positioned as he/she was discovered. Infant death reconstructions can be exquisitely painful for the parent(s) and other material parties and potentially uncomfortable for the investigator(s) involved. It is best practice for the investigator to try to preserve the dignity and emotional state of those family members involved, to advise them what the reconstruction will entail, and to permit them time to prepare themselves.
The final summary should include pertinent positives and negatives, as compiled from the above criteria, and any additional information, free text, if needed.
It should go without saying that television does not always accurately portray scene investigation. In fact, of late, the legal world has become concerned about the inflated expectations of juries with regard to the medicolegal process.
Common layperson misconceptions
Availability of answers at the scene of the crime: Cause of death isn't always apparent on the first examination, and it may take weeks of investigation to uncover the cause and reason behind a person's demise.
Turn-around time: Although strides have been made in the world of molecular biology, chemical and molecular techniques used to identify a foreign substance or sequence DNA most definitely do not occur within a 1-hour time-slot or even at the scene.
"Sherlock Holmes syndrome.": The investigator is at the scene to observe, collect evidence, and advise. Extensive deductions or posturing should wait until all facts and evidence have been assessed—once again, a process that may take weeks or months.
Misconceptions among medical professionals
Even within the realm of medical professionals, there are a few relatively tenacious misconceptions. In addition to the "artifacts" mentioned previously (see Gross Examination and Findings/Trace Evidence), there are other points that bear mentioning.
Bullet exit and entrance wounds: These should be definitively determined at autopsy (using such aids as gunpowder residue, surmised trajectory, and skeletal beveling), not necessarily at the scene. Medical responders, medical professionals, and investigators should refrain from relating potentially incorrect information to law enforcement officials. It is appropriate, however, to determine if the bullet has likely exited, so as to direct police where to search. Determining whether or not a bullet or bullets has/have exited also assists in deciding the extent and anatomic location of x-rays or other imaging that may be needed before the autopsy.
Foodstuffs or biologic secretions in the oropharynx: These do not necessarily mean that the decedent "choked." Various causes of death may permit gastric contents to passively relocate to the upper airway. Furthermore, terminal vomiting and aspiration is not an underlying (proximate) cause of death.
Ligatures and knots: Never remove ligatures or untie knots. Said objects should be removed (preferably with a clean cut away from the knot or tension point) at the time of the autopsy, in which the type of ligature and its configuration can be assessed in the context of anatomic findings.
Massive blood at the scene: This doesn't rule out a natural death. Massive hemoptysis from a pulmonary condition, for example, may account for blood at a scene, as can gastrointestinal bleeding in a cirrhotic patient. (See also Case 2: Postmortem artifacts in Gross Examination and Findings/Trace Evidence.)
Issues Arising in Court
To quote Moritz, "It is better to describe 10 findings that prove to be of no significance than to omit one that might be critical."
In fact, the importance of a particular piece of trace evidence or injury pattern may not be clear at the time of autopsy and only becomes germane to the prosecution or defense attorney(s) or following subsequent investigation. Therefore, investigators should document everything that they can, knowing a priori that their findings may later become important to the investigation. Indeed, many legal snares may arise when there is an investigative omission.
Other issues may also arise in the courtroom as a result of the following:
Breaks in the chain of evidence
Not following local and federal laws
Introduction of obscuring evidence to the scene/compromising the scene
"Talking too soon, too much, or to the wrong/too many people about scene findings" 
"Mistaking intuition for scientifically defensible interpretation" 
Confusing the objective and subjective. The corollary is that preliminary interpretation of the findings should be avoided, that is, the investigator should report "just the facts." For example, stating that the findings are "consistent with rape" doesn’t describe the nature of those findings. (For instance, it should be simply stated that "vaginal tearing and seminal deposition" is identified, without preliminary assignation of those findings to rape. Further investigation and autopsy are needed to determine whether or not those findings are consistent with rape.)  In cases of injuries/evidence of equivocal nature (ie, nonpatterned blunt force injuries) it is completely appropriate and, in fact, correct for the investigator/pathologist to say, "I have no idea what caused those injuries." Over- or misinterpretation can be even more detrimental to a case than poor observation and documentation.
Poorly selected wording and connotation: Inflammatory or editorial wording may not be intentional, but it is certainly detrimental to investigation objectivity. In addition, word connotations may be read differently than the investigator intended.
Misinterpretation of artifacts
Moritz AR. Classical mistakes in forensic pathology: Alan R. Moritz (American Journal of Clinical Pathology, 1956). Am J Forensic Med Pathol. 1981 Dec. 2(4):299-308. [Medline].
Dolinak D, Matshes E, Lew E. Forensic Pathology: Principles and Practice. Burlington, Mass: Elsevier Academic Press; 2005.
DiMaio VJ, DiMaio D. Forensic Pathology: Practical Aspects of Criminal & Forensic Investigations. 2nd ed. Boca Raton, Fla: CRC Press LLC; 2001. 16, 28-35, 40.
Jamieson A. A rational approach to the principles and practice of crime scene investigation: I. Principles. Sci Justice. 2004 Jan-Mar. 44(1):3-7. [Medline].
James SH, Kish PE, Sutton TP. Recognition of bloodstain patterns. James SH, Nordby JJ, eds. Forensic Science: An Introduction to Scientific and Investigative Techniques. 2nd ed. Boca Raton, Fla: CRC Press; 2005. 189-202.
National Medicolegal Review Panel. Death investigation: a guide for the scene investigator (November 1999). Available at http://www.ncjrs.gov/pdffiles/167568.pdf. Accessed: May 2009.
Fisher BA. Techniques of Crime Scene Investigation. 7th ed. Boca Raton, Fla: CRC Press; 2003. 43-92.
[Guideline] Davis GG, National Association of Medical Examiners and American College of Medical Toxicology Expert Panel on Evaluating and Reporting Opioid Deaths. Complete republication: National Association of Medical Examiners position paper: Recommendations for the investigation, diagnosis, and certification of deaths related to opioid drugs. J Med Toxicol. 2014 Mar. 10 (1):100-6. [Medline]. [Full Text].
[Guideline] US Department of Health and Human Services, Interagency Panel on Sudden Infant Death Syndrome, Centers for Disease Control and Prevention, et al. Guidelines for death scene investigation of sudden, unexplained infant deaths: recommendations of the Interagency Panel on Sudden Infant Death Syndrome. MMWR Morb Mortal Wkly Rep. June 21. 45:1-6. [Full Text].
US Department of Health and Human Services, Interagency Panel on Sudden Infant Death Syndrome, Centers for Disease Control and Prevention, et al. Sudden unexpected infant death investigation (SUIDI) reporting form. Available at http://files.orainc.com/?i=24&s=suidi. Accessed: May 2009.
Thomas AP. The CSI effect: fact or fiction? 115 Yale LJ. Pocket part 70. January 31, 2006. [Full Text].
[Guideline] U.S. Department of Justice. Death Investigation: A guide for the scene investigator. The American Board of Medicolegal Death Investigators. Available at http://www.abmdi.org/documents/death_investigation_guidelines.pdf. June 2011; Accessed: October 17, 2015.