NEW HAVEN, Conn. – A man who implicated two friends in the 1975 murder that sent Kennedy cousin Michael Skakel to prison has refused to testify, prompting a prosecutor Thursday to accuse him of making up the account.

Gitano “Tony” Bryant invoked his Fifth Amendment right against self-incrimination at his deposition last week in Miami and does not plan to testify at upcoming hearings on whether Skakel deserves a new trial, said Joel Denaro, his attorney.

“What it strongly suggests to us is that Mr. Bryant’s story is a fabrication and he is seeking to avoid testifying under oath for that reason,” prosecutor Jonathan Benedict said.

Skakel’s attorneys have said, in court papers, that Bryant implicated two of his friends in the bludgeoning death of 15-year-old Martha Moxley. Skakel, who was 15 and a neighbor of Moxley’s at the time of the murder, was convicted in 2002 of bludgeoning Moxley with a golf club and is serving 20 years to life in prison.

Bryant’s claim in 2003 was the latest sensation in a case that sparked numerous books and criticism that local authorities showed too much deference to Skakel’s wealthy connected family during the initial investigation.

Hope Seeley, Skakel’s attorney, said she will file a motion seeking to compel Bryant to testify.

“I think the fact that Mr. Bryant asserted his right against self-incrimination was not surprising once he hired a criminal defense attorney in light of the fact that he placed himself at the crime scene the night of the murder holding a golf club around the time of the murder,” Seeley said.

Seeley noted that her defense has a videotaped interview of Bryant giving his account. She said Bryant’s credibility was up to a jury to assess.

“I think it’s inappropriate for the state’s attorney to be issuing statements about a person’s credibility,” Seeley said.

Denaro would not comment on whether Bryant stands by his account.

“After advice of counsel, Mr. Bryant has exercised his Fifth Amendment right to remain silent,” Denaro said. “We’ll be taking the Fifth Amendment in any and all proceedings.”

Skakel, a nephew of Ethel Kennedy, is seeking a new trial based on a claim by Bryant that two of his friends may have killed Moxley. The men, Adolph Hasbrouck and Burt Tinsley, earlier exercised their Fifth Amendment rights.

Neither of the men has returned repeated telephone calls. Hasbrouck’s wife, who declined to give her name, said at the couple’s home recently that the allegation was “a lie.”

“He didn’t do anything. My husband is a good man,” she said.

Bryant attended private school with Skakel when they were teenagers. His allegation surfaced a year after Skakel was convicted of killing Moxley in their gated neighborhood in Greenwich when they were both 15.

According to Skakel’s attorneys, Bryant said he was with two friends from New York in that neighborhood the night Moxley was killed. According to court papers, Bryant said one friend had met Moxley and “wanted to go caveman on her,” and that after he left them that night, they later told him, “We did what we had to do.”

Some of the questions asked by Skakel’s attorneys during the deposition were “accusatory in nature” toward Bryant, his attorney said.

Seeley said Skakel’s defense was not accusing Bryant of committing the crime.

“Our position is Tony Bryant came forward with information that should be put in front of a jury,” Seeley said.

The petition for a new trial is separate from an appeal Skakel lost before the Connecticut Supreme Court earlier this year that argued, among other issues, that the five-year statute of limitations had expired when he was charged in 2000. Skakel’s attorneys have taken that issue to the U.S. Supreme Court.