A body is found in a dimly lit alleyway in a large Australian city: Who are they? How did they die? Did they meet foul play? Who killed them?
These are the questions we trust Australia’s forensic pathologists and allied forensic professionals to answer as they dissect the dead to reveal hidden clues about identity and cause of death.
But how do these forensic super sleuths speak for the dead?
WRITTEN ON THE SKIN
Many conclusions regarding a person’s demise can be reached through external examination of a corpse.
Wound analysis involves meticulous examination of injuries to determine the cause of death. Many wounds carry telltale signs of their origins.
Gunshot wounds leave circular entry marks on the skin and can even reveal gunpowder residue or even burn marks at close range. Bullet fragments and spray patterns may reveal clues about the type of gun used and trajectory analysis can reveal the direction of a shooter.
Stab wounds leave straight lacerations on the skin and can leave clues on the knife used, including whether it is double-edged or singe-edged or whether it was jagged so as to tear skin. In contrast to knife wounds, blunt force trauma, such as from a hammer, rarely leaves a neat mark causing the skin to break and rip unevenly.
This form of pattern analysis extends to a range of injuries. Serial killer Ted Bundy was captured and convicted partially on the basis of bite marks found one of his victims, Lisa Levy, which reflected his crooked and chipped teeth.
Even the eyes of a corpse can reveal a cause of death. Blood-shot eyes are a key indicator of strangulation.
TIME OF DEATH
Rough estimates can be given to indicate the time of death from the stage of decomposition.
Dead bodies turn pale due to lack of circulation (Pallor mortis) from 15 minutes to two hours after death. During this time, blood settles with gravity (Livor mortis) from 20 minutes to five hours after death, with internal body temperature decreasing (Algor mortis) at a rate of 2C during the first hour and 1C per hour until the body nears ambient temperature.
Rigor mortis, or the stiffening of limbs, occurs as soon as four hours after death and can maintain the body’s rigidity for about 13 hours after death before decomposition causes the breakdown of muscle tissue.
Corpse rigidity can be used as an indicator that a body has been moved — a key indicator of homicide. This was the case of a young man in India found lying on his back in a field with his arms and leg in an upward, partially sitting pose — indicating he was killed while upright then dumped later.
The final stage of decomposition is putrefaction, which is the gradual breakdown of a corpse with the aid of bacterial activity in the gut. Significant putrefaction is usually notable 48 to 72 hours after death but depends greatly on the environmental temperature. Generally, the hotter it is, the greater rate of decomposition.
Many allied forensic disciplines help to examine a dead body in ways not noticeable to the naked eye.
Complex causes of death can be deciphered by analysing corpses’ blood or other fluids, such as the transparent jelly-like tissue behind the eye’s lens. Before sophisticated toxicology testing, deaths by poisoning were often mistaken for natural deaths. This allowed sophisticated serial killers, such as Australia’s Caroline Grills, to accumulate many victims in the early 20th century.
DNA analysis and fingerprint examination are widely praised as tools to catch criminals but are equally helpful in identifying a body. For example, DNA testing was used to identify the skeleton of Matthew Leveson, a young Australian man who went missing in 2007.
Opening up a corpse is often the final stage of a forensic examination of a body, often referred to as an internal autopsy.
An internal autopsy involves a Y-incision being made on the body. The organs are then removed, examined and individually dissected if necessary. Portions of organs can also be sent for further testing and examination under a microscope.
Often, the conclusions reached during internal examination confirm observations made externally or via tests. For example, a man with external head wounds may be documented with severe brain haemorrhage or a woman expected to have died from the effects of longtime alcoholism may have indications of liver cirrhosis.
Sometimes though, a full autopsy discovers something unexpected.
The bodies of Olivier Boudin, 38, and Lucien Perot, 69, were found slumped over a half-eaten meal and two glasses of wine in the French village of Authon-du-Perche last year. The deaths raised suspicions of foul play or accidental poisoning. However, a full autopsy of the men found that Perot had choked to death on a piece of beef and the younger Boudin, who had a congenital heart condition, had died of a heart attack in shock upon seeing his friend’s demise.
This case is a good reminder that not every death is straightforward and shows the crucial role played by forensic pathologists. Indeed, the answers to a mysterious death are often just below the skin’s surface.
— Jarryd Bartle is a lawyer turned consultant and writer on sex, drugs and crime. Follow him on Twitter @JarrydBartle