Susan is still missing. We do not know where she is or what happened to her. We have left no stone unturned over the 3 ½ years of this investigation. – West Valley Deputy Police Chief Mike Powell

WEST VALLEY CITY — After more than three years of searching through 11 states and investigating more than 800 tips and "countless" hours of investigation, West Valley police on Monday announced the investigation into the disappearance of Susan Cox Powell is now officially a cold case.

“We are announcing the end of the active phase of the search for Susan. This comes after a long and arduous struggle, but it is time to do that. We have no further active leads to develop at this point,” said West Valley City Manager Wayne Pyle.

"Susan is still missing. We do not know where she is or what happened to her,” added West Valley Deputy Police Chief Mike Powell. “We have left no stone unturned over the 3 ½ years of this investigation.”

But officials promised that if any new "credible" leads into the whereabouts of the missing mother came up, they will be investigated.

To mark the closure, West Valley police revealed new details about their investigation on Monday, including the release of more than 2,000 files and "tens of thousands" of pages of police reports and other documents.

As for what police believe happened to Susan Powell, Mike Powell (no relation to the Powell family) said Josh Powell "was definitely involved" with his wife's disappearance, but stopped short of saying he murdered her.

Among the most interesting new details released Monday:

Josh's brother Michael Powell — who committed suicide in February — was "heavily investigated" and likely had "intimate involvement" in Susan's disappearance.

Michael Powell's car was abandoned in Oregon in 2009 near Pendleton. DNA evidence was found in the trunk of the car but it did not match Susan's profile.

Michael and Josh Powell had "significant" communication with each other, including sending encrypted electronic messages that police were never able to decipher.

Court-approved wire taps were used for three months, monitoring the conversations between Josh Powell and his father, Steven Powell.

Investigators do not believe Steven Powell was directly involved in his daughter-in-law's disappearance, though he may have some knowledge about what happened to her.

West Valley police met with Susan Powell's parents, Chuck and Judy Cox, over the weekend to tell them what information they planned to release, according to family attorney Anne Bremner. The Coxes are scheduled to hold a press conference Tuesday in Seattle.

"It's just hard to hear from the police that it's basically over," said Kiirsi Hellewell, Susan Powell's best friend. "I don't think (police) are giving up, even though it feels kind of like that. They're basically not going to have the full time team devoted to it."

Michael Powell

“We believe firmly that Michael Powell was involved in her disappearance. We don’t believe he was directly involved, but he had involvement at some point with her disappearance,” the deputy chief said.

Michael Powell committed suicide in February in Minnesota where he was living. Police say said he had been "deceitful" with investigators and had adamantly defended his brother.

After Josh Powell murdered his two young sons and killed himself, police say their "primary focus" became Michael Powell. Once he committed suicide, it “essentially left us with no other significant suspect” to focus on, the deputy chief said.

“Many of the details have left this world with them,” he said of the brothers.

Investigators confirmed that DNA evidence was located inside the trunk of a Ford Taurus that belonged to Michael Powell. The car had been abandoned in a salvage yard the same month that Susan Powell disappeared. West Valley police, however, didn't find out about the car until about 20 months later in August of 2011. Specialized search dogs indicated there was DNA in the car.

Several of Josh Powell's computers were seized from his home early in the investigation. But he and his brother Michael used “sophisticated” encryption technology to communicate with each other that West Valley police were never able to decode, said Deputy Police Chief Phil Quinlan.

Bremner said she wasn't completely surprised to hear Michael Powell was involved. But she was surprised as to extent of his alleged involvement.

"I had a gut reaction about him, and I knew enough about him to think that he had been involved in at least disposing of her body. I just had a bad sense," she said.

Bremner said red flags were raised for her when Josh Powell made Michael the 93 percent beneficiary of Susan Powell's $3.5 million life insurance policy.

Hellewell, however, said Susan rarely talked about her brother-in-law.

"Jennifer Graves told me that Susan would always have nice things to say about Michael. And she would say her dad is a disgusting, slimy pervert who is always ogling me when I'm around him. And the rest of them don't seem to like me, but Michael is the only one who's nice to me and she just had nice things to say about him. So it was really shocking to us that he would be at fault," Hellewell said.

Charges, odd behavior

The Salt Lake County District Attorney's Office was involved from the beginning of the investigation, police said Monday. But the evidence against the Powells was largely circumstantial. There was no crime scene and no body.

"It never materialized to the point where we had sufficient evidence to bring a criminal charge of murder to Josh Powell," said Quinlan. Investigators were in constant contact with a prosecutor assigned to the case, but the parties felt there was never enough to file charges.

Susan Powell was last seen alive at her West Valley house on Dec. 6, 2009, at 5 p.m. when a neighbor left their home after eating a pancake dinner with the family.

Josh Powell claimed he took his sons sledding at 5:30 p.m., then arrived back home at 8 p.m. At 11:45 p.m., several neighbors reported hearing the car alarm to the Powells' vehicle.

He said he left between midnight and 12:30 a.m. that night to take his sons, Charlie and Braden — who were 2 and 4 years old at the time — camping in Tooele County, about a two-hour drive from his house. Temperatures were below freezing, and a snowstorm was in the forecast. He told police he wanted to try out his new generator.

A friend of Susan Powell would later tell investigators, however, that Josh had a strong dislike of camping, according to newly released police reports.

Susan Powell was reported missing the next morning when she failed to show up for work and her sons were not dropped off at day care.

During an interview with Josh Powell on Dec. 8, police were informed "that Charlie had disclosed in a forensic interview that their mother had gone with them (camping) the night before, but that they left her there and she didn’t come back home with them,” a report states.

Among the evidence released Monday were voice mails left on Susan Powell's cellphone the day she was reported missing. Messages had already been left from friends and family members saying they're worried about her when Josh Powell left a voice mail message, claiming he forgot what day it was and why he hadn't gone to work, even though he had been called by others at that point asking about his wife's whereabouts.

"We are on our way back, and anyway, I can't believe, somehow my brain missed a day. I thought today was Sunday. So that was really, really stupid. So hopefully you got to work OK," he said. "We ran into every conceivable problem. Anyway, it was kind of a nightmare."

Susan's mother left three voice mails on her daughter's phone.

"Hey Susan, I'm just worried about you," Judy Cox said. "I'm really worried, we can't find you."

In another voice mail, the caller leaves a message: "Susan, we're all worried sick. We need to hear from you. We've been trying and trying to call."

Almost immediately, the public focused on Josh Powell's odd behavior, as did police.

From the first meeting with police, Josh Powell seemed distracted and flustered, failing to provide specific details about the days and hours before his wife went missing. In police reports, he claimed he was unable to remember what she was wearing, the names of Susan's friends, how far he drove or where he stopped on the supposed midnight camping trip he took with his sons.

When he was first questioned, Josh Powell “didn’t seem too concerned about the fact that Susan was missing,” a police report states. When he was asked, “Do you know where Susan’s at?” Josh’s response was: “Hum,” and later he said “no.”

Detectives wrote several times that Josh Powell showed no concern for his missing wife, never offered to help find her nor asked about their investigation into her disappearance.

“He asked no questions to determine what we were doing to find Susan, nor did he show any emotion whatsoever,” one investigator wrote.

When Josh was interviewed by detectives on Dec 8, 2009, he said he had called a lawyer as he drove to the police station, and was concerned about continuing conversations with officers without an attorney present. He said he felt "in over my head."

"You're in over your head because your wife is missing?" the officer asked.

Josh Powell said he was worried police were trying to "trap him," by taking pictures of his hands.

"You guys have implied some things and so it concerns me," Josh Powell said. "You've implied my hands have some kind of defensive wounds on them."

A detective the next day also noted Powell's seeming fascination with his hands: “The very first thing Josh said and pointed out to me were his hands and how he’d obtained nicks from the dry skin. I looked at his hand and acknowledged this. Josh continued to speak about them and seemed very concerned. … Never once did he mention anything about Susan, what we had done, or offer any suggestions of assistance.”

Search warrants were served on the Powell home and family vehicle on Dec. 8, 2009.

During the time police had possession of Powell's vehicle to search it, he went to the Salt Lake City International Airport to rent a Ford Focus, which he then drove for 807 miles before returning it, according to court documents.

At least two women came forward to police, saying they had had affairs with Josh Powell. One woman called police on Dec. 9, 2011, saying she had been having an affair with Josh for the past two months, since she met him at a comedy club and didn’t know she was married. “Josh told her that his wife died of cancer,” a report states. When officers asked her questions to see if she was being truthful, “She became defensive and eventually disconnected.”

Police were never able to identify the woman. Another woman told detectives, she met Josh Powell through a dating service six to eight months before Susan Powell disappeared. She said used the name “John Staley.” But when police went to her home, she wouldn’t answer the door.

Message to boys

Investigators discovered a “last will and testament” in a safe deposit box that had been handwritten by Susan Powell and dated June 28, 2008. It was titled “For family, friends of Susan all except for Josh Powell husband I don’t trust him!”

“Susan writes that she prepared this document while at work and that she feels she must leave a paper trail at work where Josh can’t destroy it,” a police report states. “Susan documents that they have (redacted) life insurance policies in the event that one of them dies in the next four years.”

One the back side of the document, Susan Powell wrote: “If I die, it may not be an accident, even if it looks like one. Take care of my boys. … I love my boys. I live for them. I choose not to cheat or do drugs because I wouldn’t want to risk losing them like (name redacted) with hers.”

One the front page she wrote: “I love you Charlie and Braden and I’m sorry you’ve seen how wrong messed up our marriage is. I would never leave you.”

A 44-minute video was also located in the safe deposit box, police wrote. It was dated July 29, 2008. Susan Powell filmed the family’s assets for insurance purposes. “At the end of this video, Susan turns the camera onto herself and says she was doing this in case something ever happened to her or her family,” a report states. “However, she hopes they live happily ever. As she says ‘happily ever after,’ Susan rolls her eyes.”

West Valley police also reviewed emails that Susan Powell had written to friends. In one dated July 18, 2008, she talked about meeting with a divorce lawyer at a friend’s house. “She also learned about people who are bipolar or have a mental illness and how to deal with them. Susan feels that Josh is bipolar and this is the reason they have problems in their relationship,” a report states.

Other emails described Josh Powell as extremely controlling, particularly with their finances. In an email dated June 2, 2009, Susan Powell “talks about how she’s running and working out and Josh wants her to run every other night to save water from showering.”

Investigation's end

Over the years, the case took West Valley police to all parts of Tooele County, Topaz Mountain in Juab County, Ely, Nev. — including the searches of more than 400 mines — as well as Puyallup, Wash., Minnesota, Mich., Colorado, Florida and Idaho as they continued to search for Susan Powell's remains.

On Feb. 5, 2012, Josh Powell killed his two sons and himself in an inferno in their rental Graham, Wash., home.

Hellewell said she has been "waiting a long time" for the release of documents from police. Bremner had made multiple requests herself over the year, on behalf of Susan's parents, to get West Valley to release details about their investigation.

Even though the search for Susan Powell is no longer an active investigation, Hellewell said Chuck Cox plans to continue conducting searches. Now that information has been released, including maps of areas searched, she said Cox plans on organizing several searches in specific locations.

Contributing: Sandra Yi

Email: preavy@deseretnews.com; mromero@deseretnews.com, Twitter: DNewsCrimeTeam