Josh Powell, the husband of missing Utah mother Susan Powell, set off an explosion at his Washington home today that killed himself and his two sons, who were there for a supervised visit, police said. 
 
 "We believe that he killed his kids and himself," Pierce County, Wash., Sheriff's Department spokesman Sgt. Ed Troyer said. 
 
 Josh Powell's lawyer, Jeffrey Bassett, said he received an email from the man minutes before the explosion that said "I'm sorry, goodbye," but he didn't see it until two hours later, when he was informed of the blast. 
 
 Bassett told The Associated Press he knew his client was upset about being denied custody of his sons at a court hearing last week, when he was ordered to undergo a psychosexual evaluation and polygraph test in order to get them back. 
 
 Click here for a look at the history of the disappearance of Susan Powell. 
 
 Graham, Wash., Deputy Chief Gary Franz told ABC News that a Child Protective Services (CPS) worker had just dropped off Powell's two sons at the house for a supervised visit. Powell took his two sons inside the house and then locked the CPS worker out. 
 
 "The children were just right in front of her as she was walking up to the door," Child Protective Services spokeswoman Sherry Hill said. "They went into the house and Josh shut the door right in front of her and locked it." 
 
 The CPS worker smelled gas, stepped away and the house exploded. The case worker was not physically harmed. 
 
 "He grabbed the kids, locked her out of the house, and immediately the house went up in flames, very quickly, very big, so we believe that Josh Powell intentionally set this fire," Troyer said. 
 
 Firefighters arrived at the scene and found the three bodies. Police are awaiting verification from the Medical Examiner's Office, but said they believe the bodies are those of Josh Powell and his two sons. 
 
 Troyer told ABC News affiliate KOMO-TV in Seattle that emails Powell sent to authorities seemed to confirm that Powell planned the explosion. Troyer did not elaborate on the contents of the emails. 
 
 The house, which was on a dead end in a quiet, residential neighborhood, has burned down to a charred frame billowing with smoke. 
 
 Firefighters are still working on putting out the fire. 
 
 "We're in overhaul phase. We're trying to get it cold so we can get inside and remove the victims so the police can come in," Franz said. 
 
 Josh Powell is the only named person-of-interest in Susan Powell's 2009 disappearance, but he has not been charged. The couple's two sons were placed in custody of Susan Powell's parents in 2011 after Josh Powell's father, Steve Powell, was arrested on charges of voyeurism and child pornography. 
 
 At a hearing Wednesday, a statement from the West Valley City, Utah, police noted that information and images were found on Josh Powell's computer that "specifically related to their children's welfare," according to ABC affiliate KTVX in Salt Lake City. 
 
 The police did not specify what the information was, but Judge Kathryn J. Nelson ruled that because of that information, Josh Powell would not be allowed to have his children back until he submitted to a psychosexual evaluation and a polygraph test, the report said. 
 
 Bassett, Josh Powell's attorney,said the ruling was unfair to his client, who has not been charged with any crimes. 
 
 "Utah was dangling the alleged content of this disk. If this disk contains what they're saying it contains why haven't they arrested my client?" he said at the hearing. 
 
 The children were to remain with Chuck and Judy Cox until Josh Powell's next hearing, which was scheduled for July. Josh Powell was allowed twice-weekly supervised visitations with his sons during that time, KTVX reported. ||||| Originally published February 5, 2012 at 2:39 PM | Page modified February 6, 2012 at 3:39 PM 
 
 Josh Powell, who has been implicated in the disappearance of his wife, was killed along with his two sons in a fire Sunday at Powell's home in Graham, Pierce County, authorities said. 
 
 Commenting has been disabled because of the sensitive nature of this story. 
 
 GRAHAM, Pierce County — Fire investigators on Monday morning were sifting through the rubble of Josh Powell's rental house, trying to determine what sparked Sunday's fire that authorities believe killed Powell and his two young sons moments after a caseworker brought them for a supervised visitation. 
 
 "The fire burned hot and it burned fast," said Pierce County sheriff's spokesman Sgt. Ed Troyer, who described the fire as an intentional act that came shortly after Powell sent an email to his attorney apologizing and saying goodbye. The caseworker told police she smelled gasoline moments before the house burst into flames. 
 
 Steve Richards, assistant chief of Graham Fire and Rescue, said crews were assessing the remnants of the home to determine what types of accelerants might have been used. Fire investigators were slowly moving around the home Monday morning, measuring areas both inside and out. 
 
 Three bodies, believed to be those of Powell and his sons, Charlie, 7, and Braden, 5, were found in the same room in the house, authorities said. 
 
 The Pierce County Medical Examiner's Office, which is to perform autopsies Monday, still needs to make positive identifications. 
 
 Troyer called the deaths "a double murder-suicide." 
 
 "What happened here was an act of evil. Do not call it a tragedy because that sanitizes it. This was a terrible act of murder involving two young children," Pierce County Sheriff Paul Pastor said near the house. 
 
 The sheriff's office plans to brief the media on the case at 2 p.m. Monday. 
 
 Powell, 36, was long considered a person of interest in the December 2009 disappearance of his wife, Susan Powell, when the couple lived in West Valley City, Utah. He had lost custody of the boys after his father was arrested last year for allegedly possessing child pornography in another house they previously shared. The boys were in the custody of the state, but living with Susan Powell's parents. However, Josh Powell was allowed supervised visitation. 
 
 Charlie and Braden Powell had begun talking to their grandparents about things they remembered from the night their mother vanished, a lawyer for the grandparents said Sunday. 
 
 "They were beginning to verbalize more," attorney Steve Downing told The Associated Press. 
 
 "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," Downing said. 
 
 About noon Sunday, Troyer said, the caseworker, a state contract worker from Foster Care Resource Network, brought the boys for a scheduled visit to Powell's house. The caseworker was assigned to the children and had previously brought them to their father without incident, Troyer said. 
 
 Powell answered the door, pulled the boys inside, slammed the door and locked it, Troyer said. 
 
 Denied entry, the caseworker immediately began banging on the doors and windows and called 911. She told police she thought she smelled gasoline. 
 
 The caseworker reported the fire started within seconds, Troyer said. 
 
 The first 911 call was at 12:13 p.m., followed by other calls. 
 
 Graham Fire and Rescue responded within three minutes, finding the house in flames with no chance to save those inside, Troyer said. 
 
 Troyer said Utah authorities might have been preparing criminal charges against Powell in connection with his wife's disappearance from their Utah home in December 2009, but he did not give details. 
 
 Buzz Nielsen, the police chief in West Valley City, Utah, whose department is investigating the disappearance of Susan Powell, said Sunday night that detectives were pursuing promising new avenues in the case and that he had hoped to seek charges by the end of the year. 
 
 "It's a circumstantial one," he said of the case, adding that his investigators had not shared their progress with Josh Powell. 
 
 Nielsen said he believes Powell was more concerned with civil-court matters, an apparent reference to the child-custody case. 
 
 Investigators from West Valley City police will be sent to Washington, said spokesman Sgt. Mike Powell, who is no relation to Josh Powell. 
 
 Asked if Josh Powell's death would forever preclude answers to his wife's disappearance, Sgt. Powell said it was important to "emphasize that Josh hasn't been cooperative with our investigation from the very beginning." 
 
 The Associated Press reported that Josh Powell's lawyer received an email from him shortly before Sunday's fire, saying: "I'm sorry, goodbye." 
 
 Attorney Jeffrey Bassett said the email arrived at 12:05 p.m. Sunday, but he didn't see it until two hours later, when others informed him of the fire. He says he knew Powell was upset after a judge last week ordered him to undergo a psychosexual evaluation, but he didn't see this coming. 
 
 Troyer said email and text messages from Powell's account were sent to a number of people, whom he didn't identify. He said investigators had no reason to doubt that Powell wrote them. 
 
 Firefighters were still mopping up the largely gutted house at 8119 189th St. Court E. late into the afternoon Sunday. Authorities began removing the bodies about 5:30 p.m. 
 
 Some people reported hearing popping sounds that sounded like gunshots at the time of the fire, while others described the noise as coming from the fire, Troyer said. 
 
 While Powell had not been arrested or charged in his wife's disappearance, he had been a person of interest in the case from the start. 
 
 Susan Powell, a Puyallup native, was 28 when she was reported missing Dec. 7, 2009. Josh Powell told police he last saw his wife around midnight, when he put their sons in a minivan and took them on a late-night camping trip in Utah's west desert in freezing temperatures. 
 
 Powell then moved back to the Puyallup area, where both his father and Susan Powell's parents live. 
 
 The boys were removed from Josh Powell's custody Sept. 22, the same day Josh Powell's father, Steven Powell, with whom the three were living, was arrested and charged with possessing child pornography. Temporary custody of the children was awarded by a judge to Susan Powell's parents, Chuck and Judy Cox of Puyallup. 
 
 Last week, a judge ordered that the boys remain in the custody of the grandparents. 
 
 Josh Powell has denied any role in his wife's disappearance and recently asked the judge to move his sons to a neutral caretaker, claiming his wife's parents — who have publicly implicated Josh Powell in their daughter's disappearance — were turning their two sons against him. 
 
 Chuck and Judy Cox declined to comment Sunday. Attorney Anne Bremner, who is representing the Cox family, said they have asked for time to grieve before speaking to the media. 
 
 Bremner learned about the deaths from a reporter in Salt Lake City. She then called Chuck Cox, who drove to Powell's house. 
 
 "It's unspeakable what he learned. It's horrific," Bremner said. "They've lost everything. They've lost their daughter. They've lost their grandkids." 
 
 Troyer said that Pierce County sheriff's investigators were coordinating with West Valley City police and that his office was seeking a search warrant for the house. 
 
 Steven Powell, who remains in jail in Pierce County, was notified of what happened Sunday and placed on suicide watch, Troyer said. 
 
 Steven Powell claimed last year that he and Susan Powell had a flirtatious relationship, and that he believed they were in love — allegations Chuck Cox dismissed as false, saying it was Powell who initiated unwanted sexual advances to her. 
 
 Troyer said the caseworker who went to the house Sunday was traumatized, and his detectives who had previously worked on the case were devastated. 
 
 "I feel bad for everybody ... so many people put so much work into this," Troyer said. Of Josh Powell, he said, "I wish he would have taken himself out and left the boys alone." 
 
 Troyer said police in Utah strongly believe Powell is responsible for the disappearance of his wife. 
 
 Denise Revels Robinson, assistant secretary of Children's Administration for DSHS, issued a statement saying, "All of us at the Department of Social and Health Services were shocked and deeply saddened by reports that Josh Powell had taken his own life and that of his two young children." 
 
 Robinson said the children were taken to the house as part of an ongoing court-ordered visitation schedule. 
 
 Robinson said the department will conduct a standard formal child-fatality review. 
 
 On her Facebook page, Susan Powell's best friend in West Valley City, Kiirsi Hellewell, expressed her grief, The Salt Lake Tribune reported. 
 
 "It's true. Feels like life is over," Hellewell said. 
 
 Denise Cox, the boys' aunt, told The Tribune she is in shock and was headed to her parents' house Sunday. 
 
 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 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 Cox and was affectionate, she said. 
 
 "He gave me a hug and a kiss and said 'I love you' before he left," she said. "It was the best feeling ever and almost brought tears to my eyes." 
 
 Seattle Times staff reporters Christine Clarridge, Michael J. Berens, Jennifer Sullivan and Amy Martinez and news researcher Miyoko Wolf contributed to this report, which also contains information from The Associated Press. 
 
 Sara Jean Green: 206-464-5654 or sgreen@seattletimes.com 
 
 Steve Miletich: 206-464-3302 or smiletich@seattletimes.com
– A Washington state man suspected in his wife's disappearance pulled his two young sons away from a social service worker at his doorstep, locked her out, and exploded his gas-filled home, according to authorities. Three charred bodies found yesterday at the blackened shell are believed to be those of Josh Powell and his sons, 7-year-old Charlie, and Braden, 5. A staffer from Child Protective Services had just turned over the boys for a supervised visit when Powell grabbed the boys. She smelled gas, quickly stepped back to phone her boss, and the house exploded, reports ABC News. "The children were right in front of her as she was walking to the door," said a social services spokeswoman. "They went into the house and Josh shut the door and locked it." The house "immediately went up in flames, very quickly, very big, so we believe that Josh Powell intentionally set this fire," said a police spokesman. Just minutes before the blast, Powell sent an email to his attorney saying: "I'm sorry. Goodbye." Powell was the only suspect after his wife, Susan Powell, vanished from their Utah home in 2009. He claimed he took his toddler sons to go camping in the freezing cold, and she was gone when the three returned. The boys were being cared for by Susan Powell's parents. Powell was just denied custody again last week, and was ordered to undergo a psychosexual evaluation and polygraph if he wanted to get them back. "What happened here was an act of evil. Do not call it a tragedy because that sanitizes it," Pierce County Sheriff Paul Pastor told the Seattle Times. "This was a terrible act of murder involving two young children." (Click to read about a possible motive.)