Feb. 5, 2011 — -- 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.