Just a day earlier, 39-year-old Gregory Coleman had checked out of yet another rehab center where he had battled the drug problem that defined his adult life. But on Aug. 7 police found him dead in a Rochester, N.Y., driveway from an apparent heroin overdose. "When someone lives the lifestyle that he led," says his brother John, 41, "sooner or later something like this is going to happen."

Coleman's sad end might have gone largely unnoticed were it not for one more twist in the sensational saga of his ex-schoolmate Michael Skakel, nephew of Ethel Kennedy. In June 2000 Coleman told a grand jury that in 1978, while he and Skakel attended the Elan School, an elite Maine academy for troubled youths, Skakel confessed to the murder of his Greenwich, Conn., neighbor Martha Moxley, 15, whose bludgeoned body was found on Halloween in 1975. (Skakel, who has pleaded not guilty, disputes Coleman's claims.)

The Connecticut Supreme Court is now reviewing a lower court's decision to try the 40-year-old Skakel, who was 15 when the murder took place, as an adult. With so much time having passed and scant material evidence, prosecutors had hoped Coleman's testimony would bolster their case. Inspector Frank Garr says the loss "shouldn't have a great impact on the case," and that a transcript of Coleman's testimony will be entered into evidence. Skakel's lawyer Mickey Sherman says he will oppose that move, in part because the witness later admitted in court that he was on heroin when he spoke to the grand jury. Substance abuse notwithstanding, says his brother, "Greg was a very smart guy. He would have made a good witness."