Forensics summary

Ever since the Great Fire of London of 1666, during which a fire at a baker’s shop resulted in a conflagration that incinerated over 13,000 homes, there has been a need for fire scene investigators. But how do these investigators find the source of something as evidence-obliterating as fire?

A proper fire scene investigation starts from the outside and moves inward. After the firefighters have stopped the fire and a structural engineer gives the go-ahead, a fire scene investigator arrives to interview witnesses, photograph the scene and scrutinize the outside of the building for evidence.

The idea of inspecting insects found on or in a corpse may be nauseating. But scrutinizing creepy-crawlies is in fact an ancient forensic tool.

The first recorded example of forensic entomology dates back to 1247, when Chinese official Song Ci produced a coroner’s handbook.

The first recorded instance of forensic pathology dates back to Julius Caesar in 44 BC, and since then forensic pathology has been an indispensable tool in determining cause of death.

An autopsy, much like investigations of fires, starts outside and moves inward. Investigators start by collecting biological samples, like hair and fingernail scrapings, and then rigorously document every scar and physical feature before making a Y-shaped incision in the body to examine the organs.

Throughout history, poison has been a choice murder weapon. It’s up to forensic toxicologists to stay abreast of new lethal substances and be able to identify them and search for antidotes.

In fact, historically, toxicology has been as much about saving lives as convicting criminals.

While fingerprinting is ubiquitous in modern forensics, the story of how it came to be is quite curious.

It all started with Henry Faulds, a Scottish missionary in Tokyo who was inspired by the way Japanese potters marked their pots with finger imprints. He discovered that these subtle prints became visible when dusted with powder.

Bloodstains do more than simply indicate that a crime was committed. They can actually tell us what weapon was used and where and how the fatal blow was struck. It can also tell us who did it.

Fittingly, the science of bloodstain analysis has some pretty bloody beginnings. In 1895, at the Institute for Forensic Medicine in Poland, Edward Piotrowski, in order to better understand blood patterns found at crime scenes, bashed rabbits on the head and had a painter document how the blood spattered. Using these paintings, he published the first paper on bloodstain patterns made from blows to the head.

Could you identify your friend by looking at their skeleton? Probably not. When a skeleton is all that remains of a body, identification becomes extremely difficult – that is, unless you’re a forensic anthropologist.

Forensic anthropology was first put on the map for the general public in 1897, during the trial of the “sausage king” of Chicago, who murdered his wife and tried to dispose of the remains in an industrial sausage vat. Forensic anthropologists were able to identify four bones found at the crime scene as being from a woman’s body. This evidence, along with the fact that his wife’s wedding ring was also found at the scene, led to his conviction.

The first thing that comes to mind when trying to describe a person is usually that person’s facial features. However, when someone dies, the body decays, causing them to lose these identifiable characteristics. Forensic scientists use facial reconstruction to fit faces to the dead.

Facial reconstruction is based on an understanding of the 22 bones that make up the human skull; such anatomical expertise enables technicians to recreate an individual’s face.

When suspects are interrogated by police, they tell all kinds of stories, both true and false, to prove their innocence. But how can police discern which stories are true and which false? Today, digital forensics has proven crucial in establishing a timeline and validating or disproving an alibi.

In the 1980s, digital forensics was largely about fraudulent business activities. All that changed with the advent of Windows 95, which made it easy for criminals to use personal computers to commit crimes.

Sometimes an investigation dead-ends: all clues and leads go cold. At this point, investigators have to get creative. In such cases, they can bring in forensic psychologists, who, rather than identifying a particular suspect, build a profile of possible suspects and point investigators in the right direction.

Forensic psychology is a relatively recent addition to forensic science. While the first offender profile dates back to 1888 (in the case of Jack the Ripper), it didn’t become a serious tool for the police until the conviction of George Metesky, the “mad bomber” of New York, who was captured after a profile created by psychiatrist Dr. James Brussel was released to the public in 1957.

Finding the evidence is only half the battle. It takes an entirely different set of skills to present that evidence in court so that it will be intelligible to jurors. Unfortunately, lawyers sometimes present evidence in a manner that suits their purposes, rather than those intended by the forensic scientist.

Being able to provide good expert testimony in a courtroom is plagued by many challenges, the first of which being the chain of custody of forensic evidence, that is, the path it took from the crime scene to the courtroom. If evidence wasn’t handled with meticulous care and proper documentation showing all the steps, it could become inadmissible in court.