CSI: Crime Scene Investigation (season 5) CSI: Crime Scene Investigation (season 5) The fifth season of "" premiered on CBS on September 23, 2004 and ended May 19, 2005. The series stars William Petersen and Marg Helgenberger. Greg begins his journey from a lab rat to a field mouse, as the Las Vegas Crime Lab faces a personnel overhaul ("Ch-Ch-Changes"), during the fifth season of "CSI". The team's final days together are plagued with more investigations into the insane and the unusual, including the discovery of an "alien" corpse just outside the boundary of Area 51 ("Viva Las Vegas"), a body washed up in a thunderstorm
CSI: Crime City discover that Monica was receiving unwanted attention from both the hotel waiter, Blake who also moonlights in the hotel spa and Pierre, another hotel guest who had shared drinks and made an unwanted play for Monica on the night of her murder. Upon further investigation CSI discover that Blake seemed to be following Monica around even swapping shifts with a colleague at the spa so that he could 'give it his best shot' with Monica and Pierre who had checked out of the hotel in a hurry leaving behind his expensive but smashed watch at the scene of the crime.