Susan Powell's Father-In-Law To Post Private Journals Online

The father-in-law of Susan Cox Powell, a 28-year-old Utah mother of two who vanished 584 days ago, said he plans to back up his theory that she ran off with another man by posting copies of her journals online.

"People don't know that there are two distinct sides of Susan. She was very ... kind of an open person in a sexual way ... with the opposite sex," Steve Powell, Susan's father-in-law, said on NBC's "Today" show this morning.

Steve Powell points to 2,000 pages of journals his daughter-in-law allegedly kept before she went missing -- journals which he said he plans to post to a new website that is launching this week.

Susan Powell was reported missing by her family on Dec. 7, 2009 after she failed to show up for her job as a stockbroker at Wells Fargo Financial. Her husband, Joshua Powell, told police he had been camping with their two children, ages 2 and 4, and had last seen his wife around midnight.

Suspicious of Joshua Powell's story, investigators named him a "person of interest" in his wife's disappearance. Several search warrants were served, including one to draw biological samples from him. Police also impounded the family van.

Joshua Powell, 34, and his two children have since moved back to his hometown of Puyallup, Wash.

The latest claims in the case come about seven months after an interview Steve Powell gave to the "Today" show, in which he said his daughter-in-law plotted her own disappearance and ran off with another man.

"I think it was definitely orchestrated," Steve Powell told the "Today" show in December.

At the time of that interview, Susan Powell's father, Chuck Cox, called the theory "ridiculous."

Another possible theory, Joshua Powell told The Salt Lake Tribune that same month, was that his wife is "extremely unstable." He blamed mental illness for her disappearance.

In regard to Steve Powell's latest theory, Cox told the "Today" show:

"I just want to make it clear that she would not leave her family. She was not sexually active or promiscuous or anything. Those allegations are completely baseless."

Cox also said he is angered that Powell said he plans to post his daughters journals online.

"I just cannot believe he would do that type of thing," he said.

Steve Powell said neither he nor his son harbor any guilt.

"We know where we stand," he said on the "Today" show. "We sleep well at night. We don't feel any guilt for anything that has to do with Susan's disappearance."

No one has been charged in Susan Cox Powell's disappearance, and police say the case remains an active investigation.

Josh And Susan Powell