The will of Robert Kardashian allegedly states that he left his diary to his children, Kim, Khloe, Kourtney, and Rob, however his widow Ellen Pearson, revealed very personal and dark stories allegedly written by Robert while he was alive.  She's apparently sold bits and pieces of the diary to various media outlets, some of which claimed that Kris Jenner (the Kardashian mother) hit Kourtney and Kim and also threatened to kill Kim.  Another alleged story that she sold to tabloids was that Kris locked Rob in a car while she went out on a date.  

If the diary was left to the sole possession of the Kardashian children (which the lawsuit claims), then Ms. Pearson would've then infringed upon their legal ownership of the diary when she sold portions to the media.  The lawsuit set against Ms. Pearson is that she give them the diary and family photo albums, as well as pay for damages.  

Kris Jenner was not left in the Robert Kardashian's will to have ownership of the diary, nor has she sued Ellen Pearson for defamation of character regarding the alleged stories of abuse that Kris inflicted on her children.

Source: tmz.com