Douglas P. Lyle

Ever wonder just how prevalent various crimes are? Or about what you should do if you witness a crime? This Cheat Sheet covers that and more, such as how investigators approach a crime scene and the tools they bring to bear in their search for clues, as well as how the medical examiner or coroner determines the cause, mechanism, and manner of death.

For those interested in digging deeper into the science and techniques of forensic science and criminal investigation, here are some excellent resources for further study. The Writers' Forensics Blog This is DP Lyle, MD's blog. Though originally geared toward writers of crime fiction, this blog is followed by forensics industry professionals and those who have an interest in crime and forensic science.

On April 5, 1994, the body of Kurt Cobain, singer/songwriter for the grunge rock group Nirvana, was found in an over-the-garage apartment at his home. His wife, Courtney Love, was in another state at the time of his death, so he was home alone. Or at least it appeared that way. He was found lying on his back, with a shotgun resting on his chest, and an obvious shotgun blast beneath his chin was the cause of death.

Sue Snow suddenly collapsed on June 11, 1986, in the bathroom of her home in the Seattle, Washington, suburb of Auburn. Paramedics found her unconscious and gasping for breath. They transported her to the hospital, where she soon died. One possible explanation for the young woman's death was a drug overdose, but she was not a known user and had taken only a couple of Extra-Strength Excedrin, a safe medication.

If you need to find out how a victim died or identify a piece of a plant found at a crime scene, you call on a forensic scientist trained in pathology or botany, respectively. Professionals who work in the various forensic biological sciences are among the most highly trained and skilled members of the forensics team.

Evidence is anything that can be used to determine whether a crime has been committed. Evidence may link a suspect to a scene, corroborate or refute an alibi or statement, identify a perpetrator or victim, exonerate the innocent, induce a confession, or direct further investigation. All evidence is not created equal.

Many criminals attempt to damage, alter, or remove their fingerprints to avoid identification or connection to prints found at a crime scene. From John Dillinger to more "common" criminals, these efforts are usually unsuccessful. Still, if, after leaving prints at a scene, the perpetrator successfully alters or damages his prints, the fingerprint examiner may not be able to make a reliable match.

The medical examiner (ME), when dealing with death, is charged with determining the cause and manner of death. The cause is what actually led to the death; the manner is by whose hand and for what purpose the death occurred. These manners can be natural, accidental, suicidal, homicidal, or undetermined, the latter being designated when the ME can't assign the death to one of the other manners with any degree of certainty.