On a Las Vegas morning, crime investigator Gil Grissom surveyed the scene of an apparent suicide by a wealthy casino heir, dusting for prints, looking for fibers — any clue to help him and his team find the true story. Through drug analysis, fiber testing and close contact with the police, Grissom determined that the dead man was killed by his brother, who hoped to get a piece of their family’s fortune. Grissom was right. The brother confessed to the crime and was sent to prison.
Close observers were led to the conclusion that crime labs can do remarkable things. And sometimes, they can. But this story wasn’t reality. It was an episode of the television show CSI: Crime Scene Investigation. In real life, crime scenes don’t always yield compelling forensic evidence and analysts don’t always catch everything. Juries, however, have come to expect that they do.