GRAHAM, Wash. - Steven Powell, the father-in-law of missing Utah mother Susan Powell, has died. Now her family worries he may have been the last person to know what happened to her.
Susan Powell's family said they're hoping he left behind a clue in her disappearance nearly nine years ago.
"I was just like it was mixed emotion, you don't know if you're happy or sad about it," said Susan's sister, Denise Ernest.
She feels there's both good and bad.
Good, that a man she considers evil is gone.
"But bad because the last legacy of hope of finding what happened to Susan is gone," said Ernest.
Susan is one of Denise's three sisters, and they were always close.
"Coping with this, it's day to day," said Ernest, who got choked up knowing next year, will mark 10 years since her sister vanished.
Denise said Susan went missing in December of 2009, shortly after telling her husband Josh Powell she planned to leave him and take their two young sons. The family was living in West Valley, Utah at the time. Investigators there have searched for her remains.
Shorlty after Susan's disappearance, Josh moved to Pierce County to live with his father Steven.
"I believe he was the last one to know what happened to him, or what happened to my sister, and where she would be right now," said Ernest.
Josh had been the primary suspect and person of interest in Susan's disappearance. Authorities say he intentionally killed himself and their two young sons, 7-year-old Charles and 5-year-old Braden, in an explosive house fire in 2012. The deaths occurred during a custody battle with the parents of his wife.
Susan's father, Chuck Cox, told KOMO he believes Josh is responsible and that Steven knew something about what happened.
"I never expected Steven to have an attack of consciousness, I don't think he'd ever divulge anything," said Cox.
"I was hoping one day he would get tired and know he was on his deathbed and he would possibly tell us where she is," said Ernest.
Pierce County Sheiff's detectives hoped that too.
"I know he did something to Susan, I have no doubt about that and I believe Steve knows where she is," said Ernest, who believes her sister was murdered and her body set on fire and dumped in the Utah desert.
Detective Ed Troyer told KOMO News when detectives learned Powell was being treated for a heart-related matter, they went to the hospital, hoping he might make a bedside confession. But, by the time they arrived he'd already passed.
"I'm hoping with him gone it will jog people's memory, see him on the news, remember the case and the public will help us start looking for her again," said Ernest.
Susan's family wants Steven Powell's possessions and property searched for possible clues.
Powell was released from prison last July after serving time for voyeurism and possessing child porn.
Police in Utah said Susan's case has gone cold, but a detective remains assigned to it.