But despite other reports claiming the two women were initially getting along, a source tells E! News, "There was always hostility between the two."
"Mariah made it clear that she wanted to be the only woman on the [judges'] panel," adds the source. "And Nicki felt Mariah was being passive-aggressive with comments toward her."
According to the source, tensions were building since the beginning "because Nicki felt as if Mariah was trying to relegate her, and it culminated/exploded in the scene that was leaked." (A clip from auditions in Charlotte shows Minaj threatening to "knock [Mariah] out" and saying, "If you've got a f--king problem, handle it!")
After the video was leaked, Idol had a meeting (with both Nicki and Mariah present) where a source said "they agreed to move forward in a positive light and not speak about the incident to the press."
So when Mariah told Barbara Walters Nicki said she would shoot her if she had a gun, Nicki "felt blindsided," says a source. "Hence why Nicki went to Twitter to express her shock. She feels Mariah is trying to get sympathy by saying she threatened to shoot her, and that the incident never happened."