CSI: Crime Scene Investigation physical evidence to solve murders. The team is originally led by Gil Grissom (Petersen), a socially awkward forensic entomologist and career criminalist who is promoted to CSI supervisor following the death of a trainee investigator. Grissom's second-in-command, Catherine Willows (Marg Helgenberger), is a single mother with a cop's instinct. Born and raised in Las Vegas, Catherine was a stripper before being recruited into law enforcement and training as a blood-spatter specialist. Following Grissom's departure during the ninth season of the series, Catherine is promoted to supervisor. After overseeing the training of new investigator Raymond Langston (Fishburne), Willows is replaced by
Crime scene scene investigation unit arrives on scene, being sure not to touch anything, an initial walkthrough is performed. This walkthrough helps the investigators get an understanding of what kind of crime has occurred. The unit notes on the presence of potential evidence and devises a plan for processing the scene. A second walkthrough is performed for the purpose of documentation. The unit will take pictures and draw sketches of the scene. Sometimes videos are taken to ensure every detail of the crime is documented. After a thorough documentation has been conducted, the CSI unit carefully collects all items that could be