Kardashian Sisters Suing Ex-Stepmom Over Father's Diary, Photo Albums (Exclusive)

"Keeping Up With the Kardashians"

October 2007: Co-produced by "American Idol" host Ryan Seacrest, "Keeping Up With the Kardashians" premieres on E!  The series would go on to spawn several spinoffs and launch a veritable media empire overseen by Kardashian matriarch Kris Jenner.

Almost a decade after the passing of Robert Kardashian, the attorney who became nationally known as a member of O.J. Simpson's criminal defense dream team, an interesting lawsuit has erupted over family property.

Robert Kardashian is, of course, the father of Kourtney, Kim, Khloé, who have all hit it big as entrepreneurial-minded reality TV stars. Two months before he died in 2003, Robert married Ellen Pearson, who is alleged to have retained some of the family's personal possessions including her late husband's diary, family photo albums and a family holiday photograph.

The items are said to document the lives of the Kardashians before they were famous and have recently turned up in the media. For example, the Feb. 4 issue of In Touch magazine had an article titled "The Secret Kardashian Diaries" while Life & Style magazine had an article described as "Feature on the life struggles of the Kardashians including Khloé Kardashian."

Pearson is said to have licensed portions of the diaries and photos to Bauer Publishing, owner of In Touch and Life & Style.

But in a lawsuit filed on Thursday in California federal court, the Kardashians and Kris Jenner say that Pearson has engineered a "despicable and unlawful scheme to hold in secret and convert, and now exploit ... private personal and copyright protected" material.

According to the complaint, at the time of Robert Kardashian's death, he bequeathed the "bulk of his personal tangible and intangible property" to his four children, including Robert Kardashian Jr.

In the Will, both "tangible" and "intangible" property are said to be defined. "Tangible" includes "clothing, jewelry, and other personal effects," "books," "works on paper," and "other items of ... personal use" and "intangible" includes "rights in literary ... properties, rights in works of art ... copyrights, publishing rights, and rights to a deceased personality's name, voice, signature, photograph, or likeness."

PHOTOS: THR's Reality Heat List

As a result, the Kardashians say that the diary and family photo albums are "incontestably" their inheritance and property.

The Kardashians say that Pearson has hidden these belongings "with the express intent to one-day capitalize and exploit the valuable property and celebrity of the famous Robert Kardashian" and as they've come to light, they've repeated requested the return.

In 2010, Pearson is said to have filed for Chapter 7 bankruptcy, and that as part of the process, she was required to list all assets and property of value. By that time, the Kardashians had achieved success as reality stars on the E! reality television series Keeping Up with the Kardashians, but "Pearson did not disclose nor list her possession of nor purported ownership of the valuable Diary and/or Photograph and/or Kardashian Family Albums."

The complaint goes on to allege that Pearson is "estopped from now claiming any ownership interest" because she failed to disclose the items in the bankruptcy process. To do otherwise, the lawsuit says, "would constitute an admission that Defendant Pearson defrauded the Court and her creditors."

The trigger for this lawsuit appears to be the recent publishing of the items in question. The Kardashians believe that in January, Pearson "sought to peddle and exploit, and disclosed to tabloid and other media, the private and valuable personal papers of Robert Kardashian." It's asserted that she was paid for an interview and provided purported rights to the the photographs.

The sisters are suing for conversion and copyright infringement and demanding a full and complete accounting and imposition of a constructive trust. At least $500,000 in damages, plus more in profits, statutory damages, punitive and exemplary damages is demanded.

The Kardashians are being represented by Martin Singer at Lavely & Singer, who tells The Hollywood Reporter, "Today's filing should serve as notice that they will vigorously defend their rights when forced to do so."

Pearson couldn't immediately be contacted.

E-mail: eriq.gardner@thr.com; Twitter: @eriqgardner