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Minor Character: Las Vegas
Ray O'Riley
Name Raymond O'Riley
Gender Male
CityLas Vegas
Occupation Head Detective
Status Deceased
Portrayed By Skip O'Brien
First Appearance Pilot
Raymond "Ray" O'Riley was a head Sergeant/Detective for the Las Vegas Police Department of CSI: Crime Scene Investigation.


Ray regularly accompanied the CSIs to various crime scenes and even helped them get some search warrants.

Season OneEdit

Ray first appears in Pilot when he assisted Grissom and Brass in attempting to catch the Bathtub Killer. Ray was more than puzzled when Grissom quickly denounced Paul Millander as a suspect. In the long run, he'd end up being right as Millander was in fact the killer.

In Boom, O'Riley interrogated the man who Nick saw assaulting Kristy. The man placed the blame of her death on Nick, but the man was later found out to be the true murderer. O'Riley took the man into custody soon after and attempted to split an attempted argument between Nick and the assailant. Catherine called O'Riley off to let Nick deal with this his own way.

In To Halve and to Hold, O'Riley assists Warrick and Sara in an investigation on the death of a male prostitute at a bachelor party. He helped apprehend three suspects at a cheap wedding chapel, but quickly left the interrogation room due to the topic of conversation: Sex.

Season TwoEdit

In Felonious Monk, O'Riley assisted the team in uncovering the mystery behind the deaths of four monks. O'Riley questioned the Chef and Ananda while the others processed the scene. He did various research into the background of Anand and found only a part of the Monk's revenue was sent to the charities. After their prime suspect was cleared, O'Riley interrogated the Chef, who killed the monks in an attempt to hide his shame that he attempted to steal the rest of the money not sent to the charities.

Season FourEdit

In Homebodies, his final appearance, he helps Catherine while she tries to connect a weapon found in a backyard to a murder that took place on the other side of town.

Season Fourteen Edit

In The Fallen, he is confirmed killed in action in 2003. His name and badge is on the LVPD Fallen officer memorial wall.


CSI:Crime Scene Investigation
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 #
Season 1 X - - - - - X - - - - X X X - - X X - X X X X N/A 11
Season 2 - - X X X X X - - - - - - - - - X - - X - - - N/A 7
Season 3 - - - - - X X - - X - - - - - - - - X - - - - N/A 4
Season 4 - X X - - - - - - - - - - - - - - - - - - - - N/A 2
Total 24


  • Since Skip O'Brien's departure from the series, he lost over 135 pounds.
  • Skip O'Brien died April 6, 2011 at the age of 60 from complications of prostate cancer.

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