Family of Missing Utah Mother Susan Powell Fights Back Against Husband's Accusations

VIDEO: The father blames Susan Powells family mounting unnecessary pressure on
WATCH Josh Powell: Missing Wife Is 'Extremely Unstable'

Harsh words from the husband of missing Utah mother Susan Powell has her family seething and adamant that she was not mentally ill when she disappeared nearly a year ago.

"It's blatantly untrue," Susan Powell's father, Chuck Cox, told "Good Morning America" today. "It's obviously a self-serving statement. It's untrue, it's all untrue."

Joshua Powell blasted his missing wife and her family in an interview this weekend with the Salt Lake Tribune. He called Susan Powell "extremely unstable" and blamed her family for keeping her in hiding and causing her to leave in the first place.

VIDEO: Almost a year has passed since Susan Powell vanished from her Utah home.Play
Josh Powell Breaks Silence on Wife's Disappearance

"She can't come back with them treating her this way," Joshua Powell said. "They want her to be perfect, a saint with no fallibility."

Joshua Powell's sister, Jennifer Graves, said she found her brother's claims that his wife was mentally ill to be ironic.

"In the Powell family, my family, we're the ones with the mental illness, documented," she said, noting that her and Joshua Powell's brother was diagnosed with schizophrenia. "I never saw Susan display symptoms," she said.

Graves, who is estranged from her own family but was close with Susan Powell and the couple's two children, has long maintained that she believes her brother had something to do with his wife's disappearance.

Although Powell is the only person of interest in the case, he said he has been unfairly scrutinized and predicted his wife would be next when she returns.

"She knows she will be chewed up like hamburger when she comes back," he told the Salt Lake Tribune.

And he stuck by his story that his wife disappeared Dec. 6, 2009, while he was out with their young sons on a middle-of-the-night camping trip in the woods during heavy snow and freezing temperatures.

Cox said that, after nearly a year, relatives are preparing themselves for the day his daughter's body might be found, but "we have the hope that she's still alive."

Loved ones get weekly updates from investigators who tell them they are still tracking down leads.

"They tell us the case is progressing," he said.

Joshua Powell's Father Blasts Missing Woman, Calls Her 'Very Sexually Motivated'

Joshua Powell's newspaper interview was the first time he has spoken publicly in months. Instead of staying in Utah to help investigators find his wife, he packed up and moved with his boys hundreds of miles away to Pullayup, Wash., to be closer to his family.

Susan Powell's mother, Judy Cox, said they are no longer allowed to have contact with their grandchildren, still in Joshua Powell's care.

"They won't let us see them," she said. "I guess they have their reasons, but we'll keep trying."

Joshua Powell's father, Steve Powell, told the Salt Lake Tribune that he believes his daughter-in-law ran off with a boyfriend, calling her "very sexually motivated."

The Coxes and Graves scoffed at the notion.

"They had their ups and downs," Cox said, but Susan Powell was "dedicated to making it work."

Graves, who visited with Susan Powell often, said she was admittedly chatty and would never have been able to keep something like that a secret.

But, Graves said, it was clear to her that her brother and sister-in-law did not have a happy marriage.

"Between Josh and Susan, there was a lot of discourse," Graves said. "They didn't have a very good relationship. Josh didn't treat her very well."

Joshua Powell last week also added a new detail to one of the case's most glaring elements when he said that a wet spot on a rug in their home that was found the morning after Susan disappeared was caused by a red stain that Susan had decided to clean before she vanished.

It was a detail that police have not corroborated.

Salt Lake Tribune reporter Nate Carlisle told ABC News that Joshua Powell, who has remained stoic and mostly silent throughout the time his wife has been missing, began to cry during the interview.

"Josh said Susan was not perfect but she was a good wife, and a good mother and at that point Josh began to cry," Carlisle said.

"He believes that the police have mishandled this investigation," he said, "by focusing on him."