NEW HAVEN, Conn. — Kennedy cousin Michael Skakel is expected to be released from prison this week while prosecutors appeal a ruling granting him a new trial in the 1975 slaying of neighbor Martha Moxley, the latest dramatic development in a case with an extraordinary history.

Skakel, the 53-year-old nephew of Robert F. Kennedy’s widow, Ethel Kennedy, has spent more than 11 years in prison. A bond hearing is scheduled for Thursday in Stamford Superior Court for Skakel, who has been serving 20 years to life and was denied parole last year.

Robert Kennedy Jr., who campaigned to overturn Skakel’s conviction, said he felt “pure joy” at the prospect that his cousin was being released. Skakel has only seen his son a handful of times since he was sent to prison, he said.

“Everybody in my family knows that Michael is innocent,” Kennedy said. “He was in jail for over a decade for a crime he didn’t commit. The only crime that he committed was having a bad lawyer.”

Kennedy said Skakel is in a tough prison and has relied on a deep religious faith to cope with his plight. He said he’s not sure where Skakel will live, noting he had to sell his house in the Catskills to pay legal bills.

“I know there is a lot of people who would open their house for him to stay,” Kennedy said.

Judge Thomas Bishop ruled last month in Vernon Superior Court that Skakel’s trial attorney, Michael Sherman, failed to adequately represent Skakel in 2002 when his client was convicted in Moxley’s death. She was bludgeoned with a golf club in wealthy Greenwich when she and Skakel were 15.

Thursday’s hearing is expected to focus on the terms and conditions of his release.

The ruling caught Moxley’s family by surprise after a decade of unsuccessful appeals by Skakel’s attorneys. Moxley’s 81-year-old mother, Dorthy, is resigned to Skakel being released.

“If he gets out on bail, he gets out on bail,” Moxley said, noting Skakel has a good prison record. “I just think he ought to serve his punishment. There’s no doubt in my mind that he did it. A little justice for Martha is not asking a lot.”

John Moxley, the victim’s brother, said he and his mother will attend the hearing.

Skakel’s attorney, Hubert Santos, has argued that Skakel should be released immediately, saying the ruling makes him an innocent defendant awaiting trial and that he is not a flight risk.