SEATTLE (AP) -- Police say they've taken their best shot at finding missing Utah mother Susan Powell. Now, her dad is hoping a review of the newly released case file -- containing tens of thousands of pages of detective reports, maps, interview transcripts and more -- might turn up something the investigators missed.
Chuck Cox told reporters Tuesday at a news conference in Seattle that a private eye has offered to help comb through the records, perhaps yielding new or overlooked clues about the sensational case.
"That's one of the reasons we wanted it: to find out what (the police) really had, because that would point us in a different direction and give us a place to search for my daughter," Cox said.
Susan Powell disappeared in December 2009, and her husband, Josh Powell, was long a suspect in the case. But last year, he killed himself and the couple's two young sons in an explosive house fire in Washington state, and 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. That left authorities with no direct suspects, and this week they announced they were closing the active part of the investigation and opening their books on the case. They insisted they never had enough evidence to charge either brother.
"We didn't have a body. We don't have a crime scene," West Valley City Deputy Chief Mike Powell said.
The documents show that police had always doubted Josh Powell's bizarre alibi. Powell claimed he wasn't home when his wife vanished because he had just left the house -- in the middle of the night -- to take their 2- and 4-year-old boys camping in the Utah desert in the middle of a snowstorm.
They describe how Powell gave muddled answers when asked where authorities should look for her, and how detectives painstakingly followed up on tips called in by hunters, campers, prisoners, other law enforcement agencies and even psychics. They checked mine shafts and shallow pet graves, tracked down a potential witness in Michigan, used wiretaps and put a tracking device on Josh Powell's van.
Detective reports also reveal that Josh Powell apparently had an affair with a woman he met through a dating service months before his wife vanished. The woman, whose full name is redacted, told them they had sex five to six times during daytime meetings, and he paid her about $800.
The revelations about the affair and about Michael Powell's potential involvement were surprising, Cox said, and he was eager to see what else was in the files.
Cox and Anne Bremner, a Seattle attorney for the family, said they continue to believe that prosecutors did, in fact, have enough evidence to arrest Josh Powell and convict him for murder. Not having a body can make it tougher to prove a murder charge, but prosecutors across the country have won convictions in such circumstances.
In this case, Bremner said, the circumstantial evidence was remarkably strong: Powell's alibi was nonsensical. He hemmed and hawed when questioned by police. He couldn't explain why he had her cellphone with the digital SIM card removed, and he couldn't explain why, in the days after she disappeared, he rented a car and drove it 800 miles.
There was also a potential motive: Josh Powell cleaned out Susan Powell's retirement accounts 10 days after her disappearance, and he had taken out $1.5 million in life insurance policies on her.
"In some ways, circumstantial evidence is the best evidence," said Bremner, a former prosecutor. "With direct evidence, you can have a witness lie. With forensic evidence, you can have problems with collection. But circumstantial evidence never lies and you can't change it.
"They could have arrested him, and they should have, based on that evidence."
Bremner told the news conference that even as Utah police close the active part of their investigation into her disappearance, federal authorities continue to review the case -- a claim that was denied by the U.S. Attorney's Office in Salt Lake City.
Bremner said she and Cox were apprised earlier Tuesday of the federal investigation by an agent who has been directly involved in the case. She said she requested permission to announce the development at the news conference, and the agent granted it. Bremner said the scope involved looking into what Josh Powell's father, Steve, knew about his daughter-in-law's disappearance.