Rebecca Zahau: Lawsuit Claims Murder at Coronado, Calif., Mansion

July 14, 2013— -- The family of Rebecca Zahau, whose body was found naked and bound at a multimillion dollar, historic mansion in Coronado, Calif., in July 2011, filed a wrongful death lawsuit in San Diego federal court alleging that she was murdered.

Zahau's mother, Pari Zahau, and sister, Mary Zahau-Loehner, are seeking $10 million in damages and a trial by jury, according to the complaint filed Friday in the U.S. District Court for the Southern District of California.

The lawsuit names Adam Shacknai and Dina Shacknai, the brother and ex-wife of Zahau's multimillionaire boyfriend Jonah Shacknai, as well as Dina Shacknai's twin sister, Nina Romano, as defendants.

Dead Woman Found Naked, Bound at Historic Mansion

Zahau, 32, was found "dead, naked, bound and gagged, with a rope noose around her neck" on July 13, 2011. She was discovered on the grounds of the Spreckles Mansion, which belonged to Jonah Shacknai, the multimillionaire founder and CEO of Medicis Pharmaceutial Corporation in Scottsdale, Ariz., the complaint said.

Zahau's mother and sister allege that Adam Shacknai, Dina Shacknai, and Romano "participated in some manner in the planning, implementation, execution and subsequent concealment of the scheme to murder" Zahau, according to the complaint. The suit does not provide any specific evidence against them.

The lawsuit comes on the heels of the two-year anniversary of Zahau's death, which had been ruled a suicide.

Jonah Shacknai is not named in the lawsuit.

Mystery Mansion Death: Family Shocked, Devastated

Authorities discovered Zahau's body in the back yard of the Spreckles Mansion on July 13, 2011. Adam Shacknai told police he found her with a rope around her neck hanging from a balcony off the main house and said he had cut her down.

Zahau's hands were bound behind her back and her feet were bound, but her hands and feet did not appear ever to have been bound together, police said. Though Adam Shacknai said she was hanging from a rope, investigators did not disclose what kind of material bound her hands and feet.

Zahau's death came just days after Jonah Shacknai's 6-year-old son Max fell down the stairs at the mansion. He died of his injuries on July 16, 2011. Police ruled his death an accident.

ABC News' attempts to reach Adam Shacknai, Dina Shacknai and Nina Romano were not immediately successful. Calls to the Zahaus and their attorneys listed in the lawsuit were not immediately returned.