Cox once defended Joshua Powell and said he didn't think he'd be capable of harming his daughter. Now, he's hoping his son-in-law will start helping authorities find her.
"It's a difficult situation when we talk," Cox said. "And I try to encourage him to use his attorney and talk to the police."
Cox said that he's confident in the police investigation, but that he doesn't know whether investigators are close to an answer.
"I have no idea where the investigation stands, really," he said.
Anyone with information regarding the case can call West Valley City Police at (801) 840-4000.