(CN) - The Kardashians are suing their father's widow for $500,000, claiming she hatched a "despicable and unlawful scheme" to hide and then exploit the late defense attorney's copyrighted diary and family photos.
Reality TV siblings Kourtney, Kim, Khloe and Rob Kardashian, and their mother, Kris Jenner, filed the copyright infringement claim against Robert Kardashian's third wife, Ellen Pearson aka Ellen Kardashian, in Los Angeles Federal Court.
Pearson and Robert Kardashian married in August 2003, less than two months before he died of esophageal cancer.
The Kardashians say their father, who famously defended O.J. Simpson during his criminal trial, left all "tangible personal property" to them in his will. They claim this includes the handwritten diary and childhood photos, which Pearson allegedly hawked to tabloids and other media for "tens of thousands of dollars."
They say Pearson has repeatedly tried to cash in on her brief marriage to their famous father by selling often false stories about them to the tabloids.
The Kardashians say they did not know about the diary until this January, when portions were reprinted in In Touch and Life & Style under headlines such as "The Secret Kardashian Diaries" and "More Heartbreak for Khloe: Secret Kardashian Diaries Revealed."
In journal entries from 1989 and 1990, Robert Kardashian "paints a heartbreaking childhood portrait of Kim, Kourtney and Khloe and a damning picture of mom Kris Jenner," according to a description on In Touch Weekly's website.
The tabloid published what it claimed were excerpts from the diary, including the following entry from Aug. 24, 1989: "Kris was kicking and beating [Kim] and and said she was going to kill her! Kim was hysterical."
The diary also reportedly details Kris Jenner's alleged affair with a younger soccer player, according to In Touch.
The Kardashians say Pearson kept the diary and family photos secret "with the express intent to one day capitalize on and exploit the valuable property and celebrity of the famous Robert Kardashian, and/or to deprive the Kardashian siblings of the benefit of private information and memories about their family, family and lives as children, all contrary to the express wishes and bequeathments of Robert Kardashian."
The property has become even more valuable since the 2007 launch of the E! reality series "Keeping Up With the Kardashians," the lawsuit states. The Kardashian sisters also appear in the spinoffs "Kim and Kourtney Take Miami," "Kim and Kourtney Take New York" and "Khloe and Lamar," featuring Khloe and her husband, basketball player Lamar Odom.
The family claims the material is potentially worth "hundreds of thousands of dollars," and that Pearson intends to license -- or has already licensed -- more diary excerpts to (nonparty) Bauer Publishing LP for publication in a "bookazine" format. (Bauer publishes In Touch and Life & Style.)
Pearson's financial situation since her husband's death has been rocky. In 2010 she filed for Chapter 7 bankruptcy "after years of unchecked spending and living off of her inheritance," according to the complaint.
The Kardashian family argues that because Pearson never disclosed her possession of the family keepsakes during her bankruptcy, she "should be estopped from now claiming any ownership."
"Any such claim or assertion now of ownership in the property in defense of this action would constitute an admission that defendant Pearson defrauded the court and her creditors in her bankruptcy action, as it would be tantamount to having hidden extremely valuable assets and property from the estate," the lawsuit states.
The Kardashians and Jenner acknowledge that Robert left Pearson a house and furnishings in Indian Wells, Calif., but insist all his personal belongings "are incontestably the personal property of the Kardashian siblings."
The siblings have since registered a copyright for the diary, and Kris Jenner did the same for an old photograph she took of Robert Kardashian with his kids at Christmas.
The Kardashians and their mother seek $500,000 for conversion and copyright infringement, and demand the return of their property and a full accounting of the money made from its exploitation, which they want held in constructive trust.
They are represented by Martin Singer with Lavely & Singer in Los Angeles.