STAMFORD, Conn. – The murder trial of Kennedy nephew Michael Skakel still may hinge on an alleged confession to an acquaintance, despite the witness’s death from a drug overdose.

Gregory Coleman, who died Tuesday, testified at a hearing in April that Skakel told him: “I’m gonna get away with murder. I’m a Kennedy” when the two attended a substance abuse center in Maine in the late 1970s.

Coleman, 39, later admitted he had injected heroin just before testifying to the one-judge grand jury whose investigation led to Skakel’s arrest on a murder charge.

Skakel, 40, is the son of Rushton Skakel, the brother of Robert F. Kennedy’s widow, Ethel. He has pleaded innocent to killing Greenwich neighbor Martha Moxley in 1975, when both were 15.

During a hearing to determine if enough evidence existed to bring the case to trial, Skakel’s defense lawyer, Michael Sherman, asked Coleman why he told the grand jury Skakel discussed the murder five or six times but later said it was only one or two times.

“I was on drugs when I came before the grand jury,” Coleman answered.

The state had been expected to rely heavily on Coleman’s testimony that Skakel admitted beating Moxley to death with a golf club. Her body was found on the grounds of her family’s estate.

Prosecutor Jonathan Benedict said Wednesday that he would seek to have a transcript of Coleman’s testimony from pretrial hearings accepted as evidence at the trial. Benedict’s office said Thursday he would not comment further.

Sherman said he will fight admission of Coleman’s testimony because it was unreliable.

“The Sixth Amendment guarantees the right to confront the witnesses against you,” Sherman said. “You can’t cross-examine a transcript.”

Some experts say authorities have a good chance at getting the testimony admitted because it was given under oath and included a cross-examination.

“I think the admission of this transcript is going to become critical,” said Todd D. Fernow, a law professor at the University of Connecticut. “If the transcript is not admitted, the state’s case is weakened – perhaps fatally so.”

Fernow, however, added that prosecutors may have additional evidence not yet disclosed. Moxley’s family has said prosecutors have other witnesses, including some who came forward recently.

Coleman’s death could actually help prosecutors because jurors would not hear and see a dramatic cross-examination of his drug abuse, some legal experts say.

“The dramatic impact of the statement attributed to Skakel is in the words themselves, which the jury may well yet hear,” said David Rosen, a trial lawyer who teaches at Yale University School of Law. “But the dramatic impact … is much more in hearing the witness cross-examined in front of the jury and that’s not going to happen.”

Jurors, though, are known to be skeptical of written transcripts of testimony, said Arthur Patterson, senior vice president of DecisionQuest, which conducts jury research.

“Jurors want to judge the credibility of witnesses by seeing that person, seeing how they handle cross-examination,” Patterson said. “Since they don’t get that opportunity, they will downgrade the credibility.”