Nancy Murray was the true main villainess from New Tricks' third season opener, "Lady's Pleasure" (airdate 17 April 2006). She was a music teacher and the wife of Stephen Murray.
Nancy was killed in a single car crash on September 26, 2001, with her death believed to be a murder orchestrated by Stephen. DSI Sandra Pullman was on the case back then, and had believed that Stephen tampered with the car in a murderous plot; a belief she maintained even in the episode's events. Stephen's need for the car back increased the suspicion, even as the episode's investigation revealed that Nancy was having an affair.
Photos of Nancy with an unknown man were shown in the beginning of the episode, with the man being later revealed as Larry Bevan, a rugby player who worked as a prostitute. It was also revealed that Larry had also engaged in encounters with Nancy's friends, Josephine Sargent and Christine Gascoine, with Josephine introducing Larry to Nancy and Christine after her one-night stand. As a result, Nancy engaged in an affair with with Larry, an affair that Stephen not only knew about, but condoned due to his wife's happiness.
However, Christine began to have true feelings for Larry, leading Christine to leak photos of Nancy and Larry in an attempt to blackmail Nancy into leaving him, which failed. Nancy's love for Larry reached the point that when Stephen informed her that he planned to take her on a three week trip to the Seychelles, she expressed despair over the thought of spending three weeks with him and away from Larry, leading to Stephen cancelling the trip. Nancy was encountered by Christine, who pleaded with her friend to leave Larry, only to Nancy to cruelly lash out at Christine, saying she was mad and stupid. On the aforementioned day in question, Nancy took the car and informed Stephen that she was meeting Christine, but in actuality, Nancy turned heel and planned to kill Christine as part of intentional murder-suicide. The psychotic villainess was set to meet Christine in front of a wine bar, and as she drove closer to her friend, the evil Nancy sped up in an attempt to run over and kill Christine. Christine avoided the attempt, leaving Nancy to be killed on impact.
The truth about Nancy's death, as well as Nancy's surprise and posthumous reveal as an evil madwoman, came after Sandra and Gerry Standing left Stephen's home. Sandra gave a speedy test run of Nancy's drive on her final day, and after coming to a stop at the wine bar, she learned that Nancy was attempting to kill herself and another person--revealed as Christine. As for Stephen wanting the car (which he did receive), it was because the car came from a time when Nancy loved him.