Law & Order (1990) : 16x9

The deaths of three women with the same name lead Fontana and Green to the nine-year-old conviction of Leland Barnes, who had shot and killed his wife in an office full of people. With two of the three witnesses against him dead and Jack McCoy on the hit list, the detectives struggle to determine how Barnes, who has been in prison the entire time, got someone on the outside to kill the only people who could keep him in jail. The investigation leads them to Leland's two sons, with surprising results.