Ep 7. Invisible Evidence

In CSI: Crime Scene Investigation season 4 episode 7, titled "Invisible Evidence," the team is called in to investigate a murder at a luxurious hotel in Las Vegas. A wealthy businessman is found dead in his room, with no obvious signs of trauma or struggle.

As the investigation progresses, the team discovers that the victim had a past history of drug addiction and was in the process of recovering. They suspect that his former drug dealer may be involved in his death, but there is no concrete evidence to support this theory.

The team also discovers that the victim's business partner, who was supposed to meet with him the night of the murder, has a suspicious alibi and may have been involved in the crime. A thorough analysis of the hotel's security footage reveals some possible clues, but the team must decipher the "invisible evidence" in order to uncover the truth.

Throughout the episode, the team uses various forensic techniques to gather evidence, including analyzing DNA, ballistics, and toxicology reports. They also interview several witnesses and suspects to piece together the sequence of events leading up to the murder.

As the investigation intensifies, tensions rise among the team members, particularly between Grissom and Catherine, who have differing opinions on how to proceed with the case. However, they must put their differences aside in order to solve the crime and bring the perpetrator to justice.

"Invisible Evidence" is a thrilling and suspenseful episode that showcases the team's expertise in forensic science and crime scene investigation. With twists and turns at every corner, viewers will be on the edge of their seats as they try to solve the mystery alongside the CSI team.