Steven Powell won't leave prison Thursday

Steven Powell won't leave prison Thursday
Steven Powell enters the courtroom for his sentencing on June 15, 2012.
OLYMPIA, Wash. (AP) - The father-in-law of missing Utah mother Susan Powell won't be released from prison Thursday, the Washington state Corrections Department said.

Steven Powell has been serving time on voyeurism charges for secretly recording images of young neighbor girls. He was sentenced in June 2012 to 2 1/2 years in prison.

May 23 was the earliest possible date Steve Powell could be released, based on sentence reductions he earned in prison for participating in programs and avoiding serious infractions, Corrections spokesman Chad Lewis said Wednesday.

To get out early, inmates must submit an acceptable release plan. Lewis said the state was still reviewing Powell's proposed plan. If it's approved, the state still requires 35 days to allow staff to notify victims and local law enforcement.

Police in Utah said this week they were closing the active part of the Susan Powell investigation and released their case file.

Susan Powell disappeared from her home in December 2009. Her husband, Josh Powell, was a focus of the investigation until he killed himself and the couple's two children last year in an explosive house fire in Graham, Wash.

Investigators turned their attention to Powell's brother, Michael, who, they now believe, helped Josh Powell dispose of Susan's body. Michael committed suicide by jumping off a parking garage in Minneapolis three months ago.

Josh Powell and his two young sons moved into his father's home in Puyallup, Wash., after Susan Powell's disappearance.

Steve Powell had a sexual obsession with Susan Powell and thoroughly documented it in journals seized by police. Officers investigating her disappearance searched his home.

Police in Utah said Monday they do not believe Steve Powell was directly involved with Susan Powell's disappearance but may know more about it than he has let on.

Police said both Steve and Michael Powell were uncooperative in the investigation.