On the evening of October 30, 1975, Martha Moxley left with friends to attend a Halloween party at the Skakel home. According to friends, Moxley began flirting with and eventually kissed Thomas Skakel, Michael’s brother. Martha Moxley was last seen “falling together behind the fence” with Thomas Skakel near the pool in the Skakel backyard at around 9:30 p.m. The next day, Moxley’s body was found underneath a tree in her family’s backyard. Her trousers and underwear were pulled down, but she had not been sexually assaulted. Pieces of a broken six-iron golf club were found near the body. An autopsy indicated she had been both bludgeoned and stabbed with the club, which was traced back to the Skakel home. Thomas Skakel was the last person known to have been seen with Martha Moxley the night of the murder and had a weak alibi. He became the prime suspect, but his father forbade access to his school and mental health records. Kenneth Littleton, who had started working as a live-in tutor for the Skakel family only hours before the murder, also became a prime suspect. However, no one was charged, and the case languished for decades. In the meantime, several books were published about the murder, including Timothy Dumas’ A Wealth of Evil; the novel A Season in Purgatory by Dominick Dunne, a fictional account of the case; and Murder in Greenwich, by Mark Fuhrman. Over the years, both Thomas and Michael Skakel significantly changed their alibis for the night of Moxley’s murder. Michael Skakel claimed that he had been window-peeping and masturbating in a tree beside the Moxley property from 11:30 p.m. to 12:30 a.m. Two former Élan School students, a treatment center for troubled youths, testified they heard Michael Skakel confess to killing Moxley with a golf club. Gregory Coleman testified that Skakel was given special privileges, saying Skakel bragged, “I’m going to get away with murder. I’m a Kennedy.”

When William Kennedy Smith was tried (and acquitted) for rape in 1991, a rumor surfaced that he had been present at the Skakel house on the night of the Moxley murder, with the clear insinuation that he might have been involved. Although this proved to be unfounded, it resulted in a new investigation of the then cold case. The Sutton Associates, a private detective agency hired by Rushton Skakel in 1991, conducted its own investigation of the killing. The Sutton Report, later leaked to the media, revealed that both Thomas and Michael Skakel altered their stories about their activities the night Martha was killed. In 1993 author Dominick Dunne, father of murdered actress Dominique Dunne, published A Season in Purgatory, a fictional story closely resembling the Moxley case. Mark Fuhrman’s 1998 book Murder in Greenwich named Michael Skakel as the murderer and pointed out numerous mistakes the police had made in investigating the case. Even in the years before the Dunne and Fuhrman books, Greenwich Police detectives Steve Carroll and Frank Garr, as well as police reporter Leonard Levitt, had become convinced that Michael Skakel was the killer.

In June 1998, a rarely invoked one-man grand jury was convened to review the evidence of the case. After an 18-month investigation, it was decided there was enough evidence to charge Michael Skakel with murder. On January 9, 2000, an arrest warrant was issued for an unnamed juvenile for Moxley’s murder. Skakel surrendered to authorities later that day. He was released shortly thereafter on $500,000 bail. On March 14, Skakel was arraigned for murder in a juvenile court as he was 15 years old at the time of Moxley’s murder. On January 31, a judge ruled that Skakel would be tried as an adult. Skakel’s trial began on May 7, 2002 in Norwalk, Connecticut. He was represented by attorney Michael Sherman. Skakel’s alibi was that at the time of the murder, he was at his cousin’s house. During the trial, the jury heard part of a taped book proposal, which included Michael Skakel speaking about masturbating in a tree on the night of the murder—possibly the same tree under which Moxley’s body was found the next morning. In the book proposal, Skakel did not admit he committed the murder. Prosecutors took words from the book proposal and overlaid them on graphic images of Moxley’s dead body in a computerized, multimedia presentation shown to jurors during closing arguments. In the audiotape, Skakel said that he was afraid he might have been seen the previous night “jerking off”, and he panicked. Though the jury heard the whole tape, during the closing arguments, the prosecutor did not play the portion of the audiotape where Skakel said “jerking off”, giving the impression that he was confessing to the murder. On June 7, 2002, Michael Skakel was found guilty of murdering Martha Moxley, and was sentenced to 20 years to life in prison. He was assigned to the Garner Correctional Institution in Newtown, Connecticut.