Rob Kardashian provocative Instagram post about Kim

"This is my sister kim , the bitch from Gone Girl,,," the 28-year-old wrote, captioning a shot from the movie of a blond Rosamund Pike covered in blood as the psycho character Amy Dunne. Rob Kardashian has never been shy about his feelings towards sister Kim, but a Keeping up with the Kardashians insider tells RadarOnline.com exclusively that his latest creepy Instagram post about his older sister “has gone too far!” As Radar reported, Rob re-launched his Instagram account on Sunday and his first post took a serious jab at sister Kim by comparing her to the sociopathic killer character Amy Dunne from Gone Girl. “This is my sister Kim, the b*tch from Gone Girl,” Rob captioned the pic.

“The Kardashian family urged Rob to take down the post, but he refuses to do so,” the source says. “At this point, it is too late anyways.”

“No one can believe that Rob would do such a thing as he did this weekend,” the source tells Radar.

“It is one thing to talk to the family about how he feels about Kim, but it is a completely different story to put her on blast like he did. Kim would never do such a thing to Rob, or to any of her other siblings for that matter.”

Another source added, “Rob’s sisters think … his lashing out is all just a ploy for attention.”

“All of his sisters love him and want him to do well,” the source continued.

Khloe Kardashian talked to Wonderwall about her brother on Saturday, before the Instagram post went up.

"I just feel, especially over the last year, Rob has become very introverted and has a kind of social anxiety," Khloe said. "He's definitely not at his happiest place that he once was, and I know he can get to that happy place and he will."