Secrets, Lies & Murder! New Tell-All Reveals What The Kardashians REALLY Knew About O.J. Simpson

Kardashian fans know all too well that O.J. Simpson was a close family friend— so close, that Kim, Kourtney and Khloe's late father, attorney Robert Sr., actually defended the disgraced former pro athlete in his infamous murder trial. But what did the tight-knit clan actually know about their pal's criminal behavior? In his new book, Kim, celebrity journalist Sean Smith reveals the Kardashians and Simpsons' eyebrow-raising connections.

Robert Sr. and his brother Tommy— Kim's uncle— befriended Simpson while playing tennis in Beverly Hills around 1970. They became business partners, and even opened a frozen yogurt shop called Joy in Westwood, Smith claims.

Uncle O.J.! Kim was conceived in early 1980, while Robert and Kris enjoyed a skiing trip in Aspen, Colorado with O.J. and his new girlfriend, Nicole Brown.

Uh oh. When Kris had an affair with soccer player Todd Waterman, the intimidating O.J. interfered on behalf of his best friend. "Todd…was concerned for his personal safety, especially after a phone call he had received from O.J. Simpson warning him to stay away from Kris," Smith writes. "O.J. apparently invited Todd over to his house to discuss things further— an invitation he had no trouble turning down."

After Nicole was brutally murdered in June 1994, Robert "rallied" around his longtime friend, and even invited him to stay in his home.

Robert was not practicing at the time, but he immediately reactivated his license in order to join O.J.'s law team. Chief lawyer Robert Shapiro realized the two men had a "special relationship."

During O.J.'s trial, Robert began to grow concerned about his children's safety. Someone wrote "n*****-lover" on his car, and "he was incensed," Smith claims.

Out of friendship? Robert worked for O.J. for free, Smith says.

Kris was expected to take the stand to speak about domestic violence in the Simpson household, but she ultimately wasn't called.

After the trial, Smith writes, Robert and O.J.'s relationship wasn't the same. Robert "realized that for years his friend had kept his troubled life with Nicole from him," Smith says. "He had seen them have only one argument the whole time he had known them." The two barely spoke after the victory party.

Loose lips? According to Smith, there were rumors that Robert was the anonymous source in many media reports about O.J. after the trial.

When Robert died from cancer in September 2003, O.J. did not attend the funeral. O.J. had attempted to call before the death, Smith claims, but Robert never answered.