How Crime Scene Investigation Works

CSI vs. 'CSI'

The cast from "CSI: Crime Scene Investigation" pose The cast from "CSI: Crime Scene Investigation" pose
The cast from "CSI: Crime Scene Investigation" pose backstage during the 2004 People's Choice Awards. Left to right: Eric Szmanda, George Eads, Marg Helgenberger, Paul Guilfoyle and Gary Dourdan Carlo Allegri/Getty Images

So, does Hollywood get it right? When asked if the TV show "CSI" accurately depicts his job­, Joe Clayton's short answer was, "No." The long answer was that the show does accurately represent certain aspects of crime scene investigation, but it leaves a lot out and it adds a lot because, well, it's Hollywood. Viewers don't want to watch a bunch of CSIs waiting around for a search warrant, and they would probably be unsatisfied if they never got a look at the suspect.

Scientifically speaking, "CSI" sometimes misses the mark. In reality, it's not possible to come up with a two-hour range for the time of death. Also, you don't just scan a fingerprint into a computer and wait for it to spit out a photo of the suspect. Fingerprint-comparison software returns several possible matches that an expert then analyzes visually to determine a definite match.

Other places where Hollywood gets it wrong involves investigative process. Crime scene investigators almost always get warrants before searching a scene. Pretty much the only scene that might not require a warrant is an apartment owned by the victim, who lived there alone and never shared the space with anyone else at any time. This means there's a lot of waiting involved -- it's pretty unusual for a CSI to arrive on a scene and just start searching. What usually happens is the CSI arrives and determines which areas need to be searched, and then someone gets a hold of the district attorney, who gets a hold of a judge, who signs whatever search warrants are requested. Once the district attorney brings the warrants to the scene, the search begins.

And the search involves the evidence, not the neighbors of the victim. CSIs do not deal with witnesses or suspects. They don't interview people at the scene, they don't interrogate anyone and they definitely don't pursue the perpetrator. These are all the jobs of the detectives on the case. Also, it's rare for a CSI to handle an entire investigation from beginning to end, even if we're just talking about the evidence. There are tons of people involved in collecting and analyzing evidence, including CSIs, forensic specialists, medical examiners and detectives. It's a rare CSI who has the time or expertise to do it all.

In Mr. Clayton's opinion, shows like "CSI" aren't making criminals any smarter. The truth is, crime scene investigation and forensic science are always trying to catch up with the criminals, not the other way around. And while there are certainly people who meticulously plan a crime and how to get away with it, Mr. Clayton's experience with crime scenes tells a different story: Most violent crimes are committed in the heat of the moment. The perpetrator is in an agitated state, possibly under the influence of drugs or alcohol, and doesn't have the presence of mind to meticulously cover his tracks. It's the rare criminal genius who studies forensic science so he can commit the perfect murder and get away with it.

For more information on crime scene investigation, forensic science and related topics, check out the links that follow.

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More Great Links


  • Baldwin, Hayden B., M/Sgt, Retired. "Basic Equipment for Crime Scene Investigators."
  • Byrd, Mike. "Duty Description for the Crime Scene Investigator." Crime Scene Investigation.
  • Byrd, Mike. "Other Impression Evidence." Crime Scene Investigation.
  • CBI Forensic Laboratory Physical Evidence Handbook, Version 4.02, September 2002
  • Colorado Bureau of Investigation.
  • "Crime pays for clean-up crew." Kansas City Business Journal.
  • "Crime Scene Investigator." Forensic Enterprises, Inc.
  • "Crime Scene Response Guidelines." Crime Scene Investigation.
  • "How to Become a CSI." ICSIA.
  • Interview with Joe Clayton, Laboratory Agent, Colorado Bureau of Investigation, November 3, 2005
  • "Latent Print Evidence Collection Guidance." Latent Print Examination.
  • "Personnel Duties and Responsibilities." Crime Scene Investigation.
  • Ramsland, Katherine. "All About Crime Scene Analysis." Court TV's Crime Library.
  • Ruslander, H.W., S.C.S.A. "Searching and Examining a Major Case Crime Scene."