HARTFORD, Conn. (AP) — Kennedy cousin and former Elan student Michael Skakel was granted a new trial on Wednesday by a Connecticut judge who ruled his lawyer failed to adequately represent him when he was convicted in 2002 of killing his neighbor in 1975.

The ruling by Judge Thomas Bishop marked a dramatic reversal after years of unsuccessful appeals by Skakel, the 52-year-old nephew of Robert F. Kennedy’s widow, Ethel Kennedy. Skakel is serving 20 years to life.

Bridgeport State’s Attorney John Smriga said prosecutors would appeal the decision.

Skakel’s current attorney, Hubert Santos, said he expects to file a motion for bail on Thursday. If a judge approves it, Skakel could post bond and be released from prison.

“We’re very, very thrilled,” Santos said. “I always felt that Michael was innocent.”

Skakel argued that his trial lawyer, Michael Sherman, was negligent in defending Skakel when he was convicted in the golf-club bludgeoning of Martha Moxley when they were 15 in wealthy Greenwich.

Skakel attended the Elan boarding school for troublesome teens in Poland, Maine, in the mid-1970s. His attendance at the school would prove pivotal in the case against him.

While always a suspect in the Moxley murder, Skakel wasn’t arrested until years later when two of his former classmates at the Elan school testified that he had confessed to them while at the school.

Elan classmate Gregory Coleman testified that Skakel bragged, “I’m going to get away with murder. I’m a Kennedy.”

But Skakel’s lawyers later introduced a transcript of an interview with another Elan student, A. Everette James, who said Skakel never confessed.

In arguing against the new trial, prosecutors contended Sherman’s efforts far exceeded standards and that the verdict was based on compelling evidence against Skakel.

John Moxley, the victim’s brother, said the ruling took him and his family by surprise and they hoped the state wins an appeal.

“Having been in the courtroom during the trial, there were a lot of things that Mickey Sherman did very cleverly,” Moxley said of Skakel’s trial lawyer. “But the evidence was against him. And when the evidence is against you, there’s almost nothing you can do.

“I don’t care if it was Perry Mason,” Moxley said. “The state had the evidence. It was his own words and deeds that led to the conviction.”

In his ruling, the judge wrote that defense in such a case requires attention to detail, an energetic investigation and a coherent plan of defense.

“Trial counsel’s failures in each of these areas of representation were significant and, ultimately, fatal to a constitutionally adequate defense,” Thomas wrote. “As a consequence of trial counsel’s failures as stated, the state procured a judgment of conviction that lacks reliability.”

Among other issues, the judge wrote that the defense could have focused more on Skakel’s brother, Thomas, who was an early suspect in the case because he was the last person seen with Moxley. Had Sherman done so, “there is a reasonable probability that the outcome of the trial would have been different,” the judge wrote.

During a state trial in April on the appeal, Skakel took the stand and blasted Sherman’s handling of the case, portraying him as an overly confident lawyer having fun and basking in the limelight while making fundamental mistakes from poor jury picks to failing to track down key witnesses.

Santos argued that the prosecutors’ case rested entirely on two witnesses of dubious credibility who came forward with stories of confessions after 20 years and the announcement of a reward. Skakel had an alibi, he said.

Santos contends Sherman was “too enamored with the media attention to focus on the defense.” Sherman told criminal defense attorneys at a seminar in Las Vegas six months before the trial that one of his goals in representing Skakel was to have a “good time,” Santos said.

Sherman has said he did all he could to prevent Skakel’s conviction and denied he was distracted by media attention in the high-profile case.

Santos contends Sherman failed to obtain or present evidence against earlier suspects, failed to sufficiently challenge the state’s star witness and other testimony and made risky jury picks including a police officer.

Prosecutors countered that Sherman spent thousands of hours preparing the defense, challenged the state on large and small legal issues, consulted experts and was assisted by some of the state’s top lawyers. Sherman attacked the state’s evidence, presented an alibi and pointed the finger at an earlier suspect, prosecutors said.

“This strategy failed not because of any fault of Sherman’s, but because of the strength of the state’s case,” prosecutor Susann Gill wrote in court papers.

The state’s case included three confessions and nearly a dozen incriminating statements by Skakel over the years, Gill said. She also said there was strong evidence of motive.

“His drug-addled mental state, coupled with the infuriating knowledge that his hated brother Tommy had a sexual liaison with Martha, and the fact that Martha spurned his advances, triggered the rage which led him to beat her to death with a golf club,” Gill wrote.

Gill said what Sherman did with his personal time was irrelevant. She said the evidence cited by the defense was not significant and that Sherman had sound strategic reasons for his decisions.

Skakel, who maintains his innocence, was denied parole last year and was told he would not again be eligible for five years.