It's a controversial murder case dating back more than 40 years, notable to most because of its connection to the Kennedy family. 

In 1975, 15-year-old Martha Moxley was brutally beaten to death with a golf club. Her body was found in the backyard of her home in Greenwich, Connecticut the morning after she attended a Halloween party at the home of the Skakel family, who lived across the street. The case went unsolved for years. 

Then-17-year-old Thomas Skakel was the last to be seen with her and was, at one time, a prime suspect. But it was Thomas' younger brother, Michael, who was ultimately charged with and convicted of Moxley's murder in 2002, a quarter of a century after the murder. Michael is Ethel Skakel Kennedy's nephew. The conviction came after two former students at a treatment center for troubled kids testified they heard Michael confess, and prosecutors played the jury a portion of a tape which gave the impression he was confessing, though the defense says he was not.  

The Skakel family fought the conviction for years, arguing that he should have been tried in juvenile court, that the statute of limitations was up, and that prosecutorial misconduct played a role in the jury's decision. In 2013, Skakel was granted a new trial and released from prison after 11 years behind bars, when a judge determined his trial lawyer failed to adequately represent him. The state's highest court will soon determine if he is to be tried again, or the conviction reinstated.

But in a new book, his cousin, Robert F. Kennedy Jr. ( @RobertKennedyJr), says he's found the real killers. Kennedy joined Jim on Monday night to discuss his book, and who he thinks killed Moxley. 

Kennedy said that there was no physical evidence tying Skakel to Moxley, "no blood, no fingerprints." The only way to convict Skakel was by a confession. Kennedy said that the two confessions that the prosecution produced were "suborned by a crooked police detective," for whom this was a career case. By the time the case was tried, the witness to the confession was dead. Therefore, no cross examination could occur. 

In 'Framed,' Kennedy explains that Tony Bryant had the information about who killed Moxley. Bryant was a classmate of Skakel for two years, before he moved to New York City. He brought two friends from New York City to Greenwich, on many occasions, to see his old friends from Connecticut. They met Martha Moxley, and Kennedy said that one of the boys became obsessed with her. Tony brought the boys six times to visit. On Halloween eve in 1975, he brought the boys back. Kennedy said they planned the sexual assault on the train there, and they picked up the golf clubs on the Skakel lawn. Kennedy said that Tony left, and 20 minutes later, the two other boys committed the murder. They confessed to Tony on many occasions, and also to another boy. 

So why didn't Tony tell the police what he knew? Kennedy said that Tony told his mother about the murder, and his mother dissuaded him from telling what he knew. His mother told him, "you're a black kid." Kennedy noted that Greenwich has a "notoriously racist police department." Bryant's mother also said that Tony brought the two boys up there. She said that if he came forward, it was highly likely he would be implicated in the murder. Kennedy said that he talked to both boys, and they admitted that they were there that night in Greenwich. But later on, the two went back and checked their diaries from 28 years prior, and they changed their stories. 

Kennedy said he found mountains of corroborative evidence to support Bryant's story. There were two hairs found on Moxley's body: one of an African American, and one of someone of Asian descent. One of the two men Kennedy suspects is African American, and the other has "Asian blood." Kennedy hopes that if these two men are innocent, they will sue him. This would lead to a deposition.

There were five people involved in framing Skakel. Kennedy said that there were 147 men on the Greenwich police force, and none had ever been involved in a murder investigation. "They made a lot of mistakes," said Kennedy. They lost the handle of the golf club, which was the murder weapon. They also lost hairs that were on her body. 

Jim asked if Kennedy felt guilty about what happened to Skakel, as many believe that Skakel was convicted because he was a Kennedy cousin. Kennedy responded that he is so invested in this case because he knows his cousin is innocent. "I knew Michael Skakel really well," said Kennedy. "I always knew that even when he was angry at me, that he was innocent." Skakel has no blood relation to the Kennedy's, but Michael Furman, known from the O.J. Simpson case, branded Skakel as a "Kennedy Cousin." Kennedy didn't know Skakel until eight years after the crimes were committed. "They were never part of our lives," he said. 

Now, Connecticut's highest court is deciding whether to retry Skakel, or reinstate the conviction. Kennedy's goal for his book is to tell the truth about this case for the first time.