CSI: Crime Scene Investigation - Leaving Las Vegas (11/24) Tuesday 3 April 21.00–22.00

The phenomenally successful Las Vegas-based forensics drama continues its seventh season. This week’s episode sees Catherine fighting to convict a man charged with murdering his mother. Meanwhile, news that Grissom is to take a sabbatical spreads through the department.

Catherine takes to the stand in the trial of Jay Finch, a man accused of murdering his mother Addie by stabbing and shooting her. Catherine explains that the knife found at the scene had four sources of blood on it – one from the victim, one from Jay Finch and two unidentified types. But despite building a strong case, Catherine is disgusted to see Finch walk free.

Catherine is now determined to reopen the case and solve the mystery of the unidentified blood. Jay Finch drove around for days after his mother’s murder, and Catherine wonders if a similar, unsolved crime in the town of Larkston might also be Finch’s doing. With Nick in tow, she heads out of town to investigate.

The evidence in Larkston soon discounts Finch’s involvement, but the local sheriff mentions a double murder that also happened at that time. The mode of killing was identical to that of the Finch case, but Catherine never heard about it because the case was closed when a man called Robert Guffey confessed to the crime.

The sheriff takes Catherine and Nick to the scene of the murders. The two victims were a woman and her mother, and the killings were witnessed by Danny, the woman’s young son, who hid in the cupboard. Outside, Nick discovers bullets in the rabbit hutch that can be compared with the one that killed Addie Finch. If they match up, it means the same person was responsible. Likewise, the unidentified blood on the knife in the Finch case could belong to these two victims.

While Nick heads back to the lab, Catherine visits Robert Guffey in prison. When she notices that Guffey gaze is focused on her blouse, she strikes an unusual deal with him to get him to talk: “Every time you answer one of my questions, I unbutton a button,” she says. Guffey readily agrees, and soon claims that his confession was coerced by the sheriff. “If I wanted to avoid the death penalty, all I had to do was tell her what she wanted to hear,” he says.

Guffey insists that he found the women dead and called 911 before fleeing, fearing that his past record of wife beating might incriminate him. Guffey’s story appears to check out when Nick confirms the bullets from the rabbit hutch do not match those from his gun. They are a match, however, for the bullet that killed Addie Finch. Catherine now calls upon the young witness, Danny, for help. Retracing his steps in the house, Danny recalls that the killer took a cookie from the cookie jar. Sure enough, inside the jar Catherine finds a bloody fingerprint – but will it lead to Jay Finch? And if Finch was the killer, the question remains: why did he stop in Larkston to murder two complete strangers?

Also in this episode, the CSIs react to the news that Grissom is to take a four week sabbatical to teach at a college. Nick is sceptical that Grissom will be back: “Sabbatical’s usually a euphemism for ‘sayonara’,” he says, and can’t resist giving him a goodbye hug in the corridor – much to Grissom’s dismay. But Grissom is confident that he is doing the right thing: “I’m a teacher without any students,” he confesses. As Grissom packs up and makes his goodbyes, his colleagues are left wondering if their friend and mentor will truly return.