CBS

Season 2: Episode 5 - Past Tense

Past Tense: Carrie and Al investigate the murder of Basir Sajadi, a NYC cab driver who was killed by a gunshot wound to the back and left in his cab. Initially, it appears Sajadi might have been killed to prevent him from acting as an informant in an FBI investigation against two potential terrorists. However, as Carrie digs into the case and cross references evidence with her memory, she becomes convinced that the man who killed Sajadi is actually a former member of the US military. Based on the location of where the cabbie's killer was picked up, Carrie manages to trace the killer to a local veteran center, where they find the name of their suspect: Cpl. John Curtis, a four-tour Afghanistan vet suffering from PTSD. Jay manages to find a drone video of the event in Afghanistan where Curtis lost his best friend in a suicide bombing, and the pieces fall into place for Carrie. She believes that Curtis's PTSD was triggered by the ringtone of his cab driver's cell phone, and he's currently in the midst of a delusional episode where he's trying to solve the murder of his best friend. Carrie and Al track Curtis to a wedding reception, where he's holding the man he believes killed his friend hostage at gunpoint, and Carrie manages to help walk Curtis through his own memories and show him that he's experiencing a delusion. Curtis then releases the hostages and surrenders to the police.