Updated

Whether Kennedy cousin Michael Skakel should get a new trial or be sent back to prison for a 1975 murder is going before Connecticut's highest court.

State prosecutors are expected to ask the state Supreme Court on Wednesday to reinstate the 2002 murder conviction against Skakel in the bludgeoning death of Martha Moxley when they were teenage neighbors in wealthy Greenwich.

Skakel, a nephew of Robert F. Kennedy's widow, Ethel, was freed on $1.2 million bail in 2013 after a lower court judge ordered a new trial after finding that Skakel's trial attorney failed to adequately represent him. He had been sentenced to 20 years to life in prison.

Judge Thomas Bishop ruled that Skakel likely would have been acquitted if his trial lawyer, Michael Sherman, had focused more on his brother Thomas Skakel. Sherman has defended his work on the case.

Prosecutors are appealing Bishop's decision to the Supreme Court.

Thomas Skakel was an early suspect in the case, because he was the last person seen with Moxley. But prosecutors have said that highlighting Thomas Skakel's relationship with Moxley would have bolstered their argument that Michael Skakel killed her in a jealous rage.

Michael Skakel, now 55, had admitted to two women that he was aware his brother had sexual contact with the 15-year-old girl the night of the murder and told one woman that is what triggered it, prosecutors wrote in court documents. But prosecutors say the trial defense decided not to focus on Thomas Skakel because there wasn't sufficient evidence.

The Supreme Court is not expected to rule Wednesday.