|Original Airdate||March 10, 2005|
Compulsion is the seventeenth episode in the fifth season of CSI.
A budding serial killer strikes again, and the CSI team tries to use new technology to solve a cold case. Nick and Catherine investigate the murder of a young boy found dead in his bed. His brother confesses to the killing, but evidence suggests that he may not have committed the crime.
Gil Grissom and his team investigate a case in which a female flight attendant has been violently raped and stabbed to death in her hotel room in which Conrad Ecklie discovers parallels to a five year old cold case.
Modern background removal techniques enable the CSIs to recover a fingerprint that leads them to a serial offender.
Despite a judge denying their request for a warrant, the CSIs manage to acquire the suspect's DNA, which doesn't match semen found at the crime scene. Analysis of this semen indicates that the likely suspect had undergone a vasectomy reversal.
Whilst interviewing the hotel manger to discuss bleach found at the scene, Grissom notices that the manager's children's ages significantly differ.
A question about his vasectomy leads the manager to clam up and refuse to provide a DNA sample. In the interview room at the police station, Grissom tells the suspect and his lawyer about premeditated psychopaths.
As the lawyer is pointing out they have no evidence tying the suspect to the crime, Sara Sidle wheels in a suitcase, the sight of which causes the hotel manager to accuse the police of breaking into his car.
His lawyer says that if they did break into his car to retrieve the suitcase, the entire case must be thrown out. Sara opens the suitcase and reveals that it is identical to the victim's, with nothing but a tape recorder inside. The hotel manager's words, however, have already given the CSIs probable cause to search his car, sealing their case.
Meanwhile, Catherine Willows' team assists Detective Cavaliere in the investigation of a young boy who was savagely beaten to death with a pipe while in his own bed.
Nick Stokes and Cavaliere get into a heated argument over their methods of finding the culprit. Cavaliere gets a confession after coming down hard on the brother of the victim—too hard, Nick believes.
Nick decides to investigate the evidence, turning up a neighborhood bum who has been causing a nuisance. He is found wearing the boy's father's blood spattered jumper.
Unable to pick between the bum, the father or the boy's brother, the team beat a bloody mannequin to gain insight as to the likely suspect.
The pattern of the spatter leads them to identify the boy's brother as the killer. After meeting with the father, the brother admits it was because the victim told everyone about him wetting the bed.
As the bleach was unique in its composition, a fact made evident by its odor, Grissom replies that it is the first thing Hodges has done to impress him.
- When we are shown the flashback of Matt killing Ty, you can see sunlight coming through the window, but when the CSI team is looking over Ty's body, they say his time of death was around midnight, so there should have been darkness coming from the window.
- About the middle of the episode, when Nick and Warrick are interviewing the couple in their living room, on the right side of the room you can see a crew member moving behind the glassdoors.
- When Greg collects the suspect's discarded coffee cup from the table at the cafe, he isn't wearing any gloves which would have contaminated the DNA evidence.
- Just after the opening credits, when Greg hands Grissom the "Phillips" Screw driver in the bathroom, it is clearly A) Not a Phillips Bit and B) Not the same head that Grissom uses to unscrew the drain cover.
- Since Catherine is the head of the swing shift (4:00pm-12:00am), there's no valid reason for her getting a case that begins at the crack of dawn.
- Near the end of the episode, the CSIs verify a blood spray pattern by hitting a dummy with a pipe. When Nick takes his turn, we first see a side-on shot where the upper half of his sweater is spattered liberally with blood. The camera then cuts to a head-on shot, where Nick's sweater suddenly has significantly less blood on it.
- Greg (to Sara): I just got the call. Where's Grissom?
- Sara: Bathroom. (Greg looks puzzled) Working the.. uh.. case.
- Brass (to Grissom): Take a whiff.
- Grissom: Smells clean.
- Brass: Smells like a hospital.
- Sara: Bleaches and deodorizers. Killer attacked the victim, then cleaned and sanitized the room.
- Grissom: Ah, but here's the smell of the blood still, and all the perfumes in Arabia will not sweeten this little room.
- Martin Hawkins (to Matt): I want to know why?
- Matt Hawkins: Dad...
- Martin Hawkins: Why, damn it. Ty looked up to you, he...he loved you.
- Matt Hawkins: He told. He told everyone.
- Martin Hawkins: That you wet the bed?
- Matt Hawkins: Shut up! (pauses for a second, then bursts into tears) Dad, I'm sorry. (cries some more)
- Detective Cavalier: You owe me an apology.
- Nick: I'm sorry... (pause) that you feel that way.
- William Petersen as Gil Grissom
- Marg Helgenberger as Catherine Willows
- Gary Dourdan as Warrick Brown
- George Eads as Nick Stokes
- Eric Szmanda as Greg Sanders
- Jorja Fox as Sara Sidle
- Paul Guilfoyle as Jim Brass
- Robert David Hall as Dr. Al Robbins
- Aisha Tyler as Mia Dickerson
- Jason Segel as Neil Jansen
- Wallace Langham as David Hodges
- José Zúniga as Detective Chris Cavaliere
- Tina Lifford as Judge Witherspoon
- Marc Vann as Conrad Ecklie
- James Patrick Stuart as Attorney Adam Matthews
- David Berman as David Phillips
- Larry Sullivan as Officer Akers
- Joseph Patrick Kelly as Officer Metcalf
- Victoria Prescott as Trudy Tremont
- Lee Tergesen as Martin Hawkins
- Wil Wheaton as Walter
- Diane DiLascio as Yvonne Hawkins
- Tamara Clatterbuck as Michelle Archeson
- Cleo King as Lucy
- Andy Gobienko as Matt Hawkins
- Erin Matthews as Martha Krell
- David Newsom as Hayden Michaels
- Stephen Baldwin as Jesse Archeson
- Gillian Shure as Sue Stein
- Cody Weselis as Ty Hawkins (uncredited)