Thousands of images and emails on his Washington state government-issued laptop provide a small glimpse into his increasingly scrutinized world. Authorities said this week that he is a person of interest in her 2009 disappearance in Utah.
The files, obtained by The Associated Press as part of a public records request, portray Steve Powell as a meticulous worker who gathered photos by the thousands and had his life upended by the constant inquiries that ensued after Susan vanished.
He is now in jail on voyeurism and child pornography charges -- and on suicide watch.
Powell's son and Susan's husband, Josh, killed himself and the couple's two young sons in a gas-fueled inferno Sunday that a prosecutor considers an admission that he killed his wife.
Investigators have been trying to piece together Josh Powell's last days. Court documents filed Friday say that a search of a storage unit he rented turned up a stained comforter that tested positive for blood in initial exams. Investigators planned further tests.
Until this week, authorities have only publicly discussed Steve Powell in relation to the charges he now faces. But a warrant and emails indicate that he has been dragged deeply into the Utah investigation surrounding his son, and police say they want to interview him to see if he knows anything about his daughter-in-law's disappearance.
"He may or may not have information that may be beneficial to us," said Sgt. Mike Powell in West Valley City, Utah, where Josh and Susan Powell lived at the time of her disappearance. Sgt. Powell is not related to the family.
The September warrant sought details specifically from Steve Powell's laptop, which he used in his job helping coordinate purchase and placement of school furniture. It also requested a search of state-owned vehicles that Powell may have driven.
Steve Powell said last year that he had a flirtatious and somewhat sexual relationship with Susan Powell. Her parents said she thought he was a creep and moved to Utah in part to get away from him.
In a search of Steve Powell's Washington state home last year, authorities found explicit images on his computers and images of people being photographed without their knowledge. Among them were pictures of Susan Powell.
Those findings led to the voyeurism and child porn charges, to which he has pleaded not guilty. The state took custody of Josh Powell's boys and turned them over to Susan's parents, Chuck and Judy Cox.
Powell's work computer has a batch of photos of Susan Powell, though none appear to be sexual. They depict her and the kids opening Christmas presents and out during Halloween. A few show Susan Powell and the kids more formally dressed. It's not clear who the photographer is.
An attorney for Steve Powell did not return a call seeking comment.
Pierce County Prosecutor Mark Lindquist, who is overseeing the voyeurism prosecution, said it's his understanding from the images collected that Susan Powell is the subject of much of Steve Powell's photographic attention.
He said the many images of Susan Powell might be of some interest to Utah authorities, but he has seen no evidence connecting Steve Powell to what he calls Susan Powell's murder.
Emails show that Powell was actively working in the days around when Susan Powell disappeared on Dec. 6, 2009. He responded to emails the next morning, even drawing praise from a manager for pointing out an oversight related to holiday cards.
A school district contact that he was scheduled to meet with that week said she never had any problems with Steve Powell and never realized he was Josh Powell's father until seeing him later on television.
"He was always professional and did what he was supposed to do," Susan Garthwaite said.
A couple weeks later, on Dec. 21, he wrote to a colleague about how Josh and the boys had moved back to live with him and that the children were traumatized by the bright lights of the media and "the searches."
"Even with Josh and the boys here, I am so numb much of each day that I have to put myself on auto-pilot to get things done," he wrote. "I know there are people with worse problems, but when it's yourself experiencing the suffering, you can't just tune it out."
He then added, "I still need to send a card to Susan's folks."
Her parents said no such card ever arrived.
Powell later described to a colleague in 2011 how he and Josh were baffled by the ongoing investigation in Utah.
The case appeared to take an increasing toll on him. He requested time off around the time of the search warrants and then later complained of harassing phone calls from Utah that accused him of "harboring a criminal, accusing my son of murder."
In the search warrant used to examine Powell's belongings, authorities said, they were investigating a murder in West Valley City, Utah, though nobody has ever been charged with a crime.
Utah investigators say the case remains open and they are still publicly calling it a "missing persons" matter.