Ty Hansen Sues His Dead Dad Over Mother's Disappearance 50 Years Ago

Dec. 15, 2009 — -- Ty Hansen believes he knows the real story behind his mother's disappearance nearly 50 years ago.

Hansen believes Joan Hansen didn't run away from her family when he was just 2 years old, but was killed by his father because she had filed for divorce.

To prove his case, Hansen is suing his father for damages -- despite the fact that Robert Hansen is dead.

Hansen insists he just wants the truth of his mother's disappearance to finally be heard and his father's culpability to be legally settled. He acknowledges, however, there are several million dollars at stake.

"I want justice for my mother. I want her story to be told," Hansen told ABCNews.com. "I don't want this to be swept under the rug like it has been for the last 47 years."

Hansen says he was raised by his father telling him and his two siblings that his mother had deserted the family, but a very different story emerged when he began researching his mother's story 15 years ago.

What Hansen found was divorce papers that indicated violence between his parents, and the fact that his mother was reported missing when she didn't show up for a hearing regarding the separation. In addition, his mother's friends who knew her at the time of her disappearance said she had vowed she'd never desert her kids.

Patricia Martin, one of Joan Hansen's best friends, claims she spoke to Joan Hansen moments before she was murdered.

"We were speaking on the phone and all of sudden Joan said 'Oh my God,' then there was silence and then I heard her holler 'Don't!'" said Martin, 76. "She kept saying 'he's coming' and then she started screaming and the phone went dead."

"I have no doubt what happened to Joan," said Martin. "I know he killed her."