The fire broke out about 12:30 p.m., Washington time, just moments after a social worker had arrived with the boys 7-year-old Charlie and 5-year-old Braden for a supervised visit with their father.When the boys entered the home, Josh Powell locked out the social worker, who pounded on the door and a window, then tried to call Josh Powell's cell phone, Troyer said.
The house "lit up" about three minutes after the social worker was locked out, and it burned with a ferocity that prompted witnesses to believe the home had exploded, Troyer said. The social worker who was not physically injured called 911, then went to a neighbor's home, Troyer said.
The three bodies were later found in the same room in the middle of the home, Troyer said.
Josh Powell's death could mean that the disappearance of his 28-year-old wife Susan Powell from their West Valley City home in December 2009 will never be solved.
West Valley City Police Chief Thayle "Buzz" Nielsen, in an interview with KUTV 2, struggled to find words for the horror of what happened.
"This was just evil, this was a terrible thing," he said. "He wiped out the whole family. So selfish. Our guys are struggling through this. I don't know, it hasn't hit us yet."
Nielsen said he and other members of the department will be going to Washington for a strategy session with sheriff's officers there.
"Then we need to say where we're going to go," Nielsen told KUTV. "We need to get some closure for us on our criminal case, so in the next couple weeks we'll probably sit down and have a decision made and go meet with the judge and prosecutors on where we're at."
An email Josh Powell sent to his attorney and to a number of other people helped police confirm that he deliberately set the fatal fire.
Jeffrey Bassett, who represented Josh Powell in the custody case, said he received a three-word email from his client just minutes before Powell and his two boys died in the fire.
"I'm sorry, goodbye," the email said.
The message arrived about 10 minutes before the fire broke out, but Bassett didn't see it until two hours later, when others told him Josh Powell and the boys had been killed.
Bassett said he knew Josh Powell was upset after a judge last week ordered that his sons remain in the custody of their grandparents, Chuck and Judy Cox. The judge also ordered Josh Powell to undergo a psycho-sexual evaluation and a polygraph test in connection with explicit images found at his West Valley City home.
Josh Powell also may have been feeling pressure in his role as the only person of interest publicly named by police in the disappearance of his wife from their Utah residence in December 2009.
But in documents filed by Josh Powell just five days ago in the Pierce County custody case, he defended himself as a "stable and loving parent," despite the hardships he was facing since his wife's disappearance.
"I miss my wife, and so do many other people," he wrote to the court. "It has created a very difficult circumstance for our entire family. I have recently heard rumblings that some people are dipping deep down to the bottom of the barrel in a desperate effort to find and manufacture fault with me due to their attitudes.
"A lesser person would fall under the intense scrutiny that I am facing, but apparently my inherent resilience as a person makes it increasingly difficult for them to pursue their agendas. I am standing tall for my sons, but it deeply hurts to face such ridicule and abuse."
The Coxes were "absolutely devastated" by the loss of their grandchildren, according to their lawyer.
"It's the most horrifying thing you can imagine happening," said Steve Downing, who represented Susan Powell's parents in the custody fight. "They were always very fearful of him doing something like this, and he did it."
Later Sunday, Downing said the children had started talking to their grandparents about things they remembered from the night their mother vanished.
"They were beginning to verbalize more," said Downing. "The oldest boy talked about that they went camping and that Mommy was in the trunk. Mom and Dad got out of the car and Mom disappeared."
Susan Powell was reported missing Dec. 7, 2009. Josh Powell who has denied any involvement in her disappearance told police he last saw his wife around midnight, when he put their sons in the family's minivan and took them on a late-night camping trip during freezing temperatures in Utah's west desert.
Kirk Graves, Josh Powell's brother-in-law and the husband of Jennifer Graves both of whom had been estranged from Josh and believe he killed Susan Powell said he views the fire as proof that Josh Powell killed his wife.
"In my personal opinion, this is Josh's admission that he did it," Graves said. "I know others won't interpret it that way, but I know that is what this was."
Graves said he and his wife had been pleased the boys would be able to stay with Coxes.
"Josh didn't feel the same way, I guess," Graves said.
Graves said they got confirmation of the fire from Chuck Cox, who went to Josh Powell's home and observed it burning.
"We're still in shock," Graves said. "We're almost shaky."
They visited their nephews over Thanksgiving in Washington, and had spoken to them on the phone since.
Graves said of Josh Powell's mother, Terrica Powell, "She's not doing well."
Graves said he plans to go Washington and be there for the Coxes and help with funeral arrangements.
Kiirsi Hellewell, Susan Powell's best friend in West Valley City, said she screamed out in grief after confirming the boys were killed. She now wonders if there will ever be answers to the fate of her missing friend.
"I'm so furious with Josh for so many reasons," Hellewell said. "If he's going to take such a cowardly and selfish way out of this, I wish he would have left a note to explain what happened. Now we still don't know, and now he's gone and we don't have any way of getting answers ... Not only that, he murdered two little innocent boys. If he wanted to kill himself, he should have done that, but how dare he do something so horrible, so evil?"
Hellewell called Josh Powell "the kind of person that only cares about himself. "
"He never really loved his boys. To him, they were possessions," she said. "They were something for him to own and possess and to control. Once that control was taken away [at the custody hearing last week] ... he just felt like if I can't have them, nobody is going to."
Hellewell said she spoke to Chuck Cox, Susan's father, moments after she heard of the fire to ask if the news was true. Cox told her he wasn't sure and was on his way to the home. He called Hellewell back moments later and said a Washington sheriff's deputy had just confirmed it.
"He was in a state of shock," Hellewell said. Cox told her his one consolation is that the boys are with their mother again, she said.
Like the Coxes, Hellewell has long believed that Josh Powell had something to do with Susan's disappearance.
Hellewell said she was relieved last week when a Washington judge decided to leave the two boys with the Coxes at least through July. Still, she said there was fear Powell might be furious.
"We've all been very, very worried about their safety," Hellewell said of the two boys.
In a December court filing, Josh Powell asked the court to move the boys to a neutral caretaker and expressed frustration with the slow pace of efforts to reunite him with his sons. He claimed the Coxes were out to "destroy our loving relationships as a natural family unit."
He said the Coxes' hatred of him "pervades their household, their social circles, and their public comments."
Josh Powell claimed the Coxes were turning his two sons against him.
"By living in the Cox house, the boys are exposed to the Coxes' overwhelming attitude of hatred toward me, and it is seriously traumatizing my children," he said.
Supporters of Josh Powell and his family previously described them as an "all-American family," saying they saw nothing disturbing in his interaction with his sons.
"Josh is a loving, devoted, protective, caring father," wrote Alina Powell, Josh's sister in an affidavit filed in the custody case last September.
Terrica Powell, Josh's mother, also provided an affidavit that described her son as an "engaged" father.
According to Sherry Hill, spokeswoman for the Washington Department of Social and Health Services, no one had any idea that Josh Powell had anything like this planned.
"We would have gone back to court had we any indication that Josh Powell was suicidal," Hill said. "It's a terrible tragedy that these poor children especially had to suffer and die because of the actions of their father."
She said the woman who was to supervise Sunday's visit between Josh Powell and his children was not a Child Protective Services employee but a contract worker with a private agency.
"She pulled up in the car, and the kids ran out ahead of her," Hill said. "Josh Powell closed the door and locked it. She wasn't able to get in, and that's when she smelled gas."
Josh Starkey, who lives in the neighboring Washington town of Puyallup, saw the black smoke billowing from the fire and drove about five miles to get to the scene. He said he arrived about the same time as fire trucks.
"The house was gone," he said. He took some photos of what he thought was just a huge fire, and his children left the area quickly as the smoke made it difficult to breathe. He later found out whose home it was.
The Powell's oldest son attended Carson Elementary School in Puyallup, where a vigil was held Sunday night. The younger son was not yet enrolled in school.
Neighbor Jessica Lyon, 18, said she was laying on the couch in her home when the fire erupted occurred. "The whole house shook. It was like an earthquake. It was huge," Lyon told the News Tribune.
Lyon looked outside and saw the insulation from the house raining down.
More than 30 neighbors gathered around the scene before firefighters arrived and reported hearing two more explosions after that. There were at least three explosions total, neighbors told the Tacoma paper.
Denise Cox, the boys' aunt, said Sunday she was in shock over the news and was headed to her parents' house in Puyallup on Sunday afternoon.
Denise Cox had just seen her nephews at her parents' Saturday and joked about leaving the house because Charlie commanded her to come back to see him on Sunday. She said it was funny that he didn't ask her to come back, he told her to which the family thought was cute.
On Thursday, Braden Powell spent time with Denise Cox at her Washington house and was affectionate, she said.
"He gave me a hug and a kiss and said, 'I love you,' before he left," she said last week. "It was the best feeling ever and almost brought tears to my eyes."
Josh Powell's boys were initially removed from his custody Sept. 22, the same day Josh Powell's father, Steve Powell, 61, with whom the three were living, was arrested and charged for voyeurism and possessing child pornography.
Steve Powell was notified at the jail of the fatal fire.
Troyer, with the sheriff's office, said that Steve Powell was asked if he knew anything about it. He was not cooperative and "called us a few names," Troyer said, adding that Steve Powell was placed on suicide watch.
Salt Lake City attorney Scott C. Williams, who represented Josh Powell in Utah, said he didn't have any comments "beyond the obvious."
"It's a terrible, terrible circumstance," Williams said. "Tragic, heart-rending for anybody to learn."
And the fact that the children were involved "compounds the tragedy."
Williams would not say when he last spoke to Josh Powell. He added that he had the "same curiosity" about what West Valley City police might have uncovered in their investigation of his client.
"They never shared the results of their investigation," Williams said.
At the Friends and Family of Susan Powell website, people from around the country posted comments expressing shock and sympathy for the Cox family as the news broke.
"Those little boys are with their Mom in Heaven. I just don't understand how a father can be so evil. My heartfelt sympathy to Susan's parents, her family and friends. May they find peace in their hearts in time when they reflect upon the happy memories they shared when Susan was here. RIP and fly with the angels," wrote Lorraine Troy of Albany, New York.
"My heart breaks for the grandparents," said a post from Chris Hoffman-Fagundes of Tacoma, Wash., who also wondered why the visit did not occur at a public place and expressed concern for the social worker who brought the boys to the home. "My heart breaks, tears streaming."
West Valley City police sent a news release later Sunday reminding the public that a $10,000 reward for information leading to the whereabouts of Susan Powell still stands.
"We're looking, and we're still working it. It's not closed for us, and it's still active," Chief Nielsen said.
But when asked if he thinks Susan Powell could be alive, Nielsen told The Tribune: "There's nothing to indicate that she's alive. There's not a good chance that she's alive."
The Associated Press contributed to this report.
Home video of the fire:
Aerial images of the home: