In a sneak peek at Sunday’s season 14 premiere, Kim and Kourtney Kardashian travel to Cleveland to visit Khloé Kardashian, who spends much of time there with her boyfriend, Cavaliers player Tristan Thompson — but they’re interrupted by a news alert about Caitlyn’s then-unreleased memoir, The Secrets of My Life.
“It says in Caitlyn’s book Robert Kardashian knew O.J. Simpson was guilty, but joined the defense team to get back at his re-married ex,” reads Kim, 36. “Robert told Caitlyn in secret after the O.J. murder trial that he believed his friend was guilty.”
“That’s not true!” interrupts Khloé, 33. “Like, what?”
“Like, to sell a book, you’re gonna make something up?” says Kourtney, 37.
“Dad so believed in him,” Kim says. “It is so shady that Caitlyn came over and gave me the book, and then on the phone she said, ‘Well, the final version has a few more things in it, but don’t worry, it’s nothing about you.’ So she lied to me, because that is about me, if it’s about our dad.”
“I have always had Caitlyn’s back,” she tells her sisters. “But she is a liar. She is not a good person.”
In her memoir, which was released April 25, Caitlyn claimed the late Robert Kardashian Sr. once implied he thought his friend O.J. Simpson was guilty of having killed wife Nicole Brown Simpson and waiter Ron Goldman — despite having served as the NFL star’s defense attorney in his 1994 murder trial.
Caitlyn, 67, wrote that she was in the car with Robert in the late ’90s — following Simpson’s initial acquittal and later conviction of manslaughter in a civil trial — when he allegedly said, “I would’ve been okay with it if they had gotten him in the first trial.”
“The implication was obvious that [Robert] believed O.J. was guilty,” she added.
Caitlyn went on to speculate whether part of Robert’s motivation behind defending Simpson was to obtain some form of revenge against his ex-wife Kris Jenner, who was close friends with Brown Simpson.
“I wonder if it was his way of saying to [Kris] what I think she was saying to him when she married me: a big f— you,” she wrote.
Keeping Up with the Kardashians season 14 premieres Sunday at 9 p.m. ET on E!
Check out the preview for the episode below.
This article originally appeared on PEOPLE.