The monster who killed himself and his two young sons in a Washington house fire two years after his wife vanished reportedly attacked the boys with a hatchet before setting the blaze.
The sons of Josh Powell, who were just 7 and 5, suffered what police described as "chop wounds" to their heads and necks before the Graham, Wash., home went up in flames as a helpless social worker looked on Sunday. The cause of death for all three is believed to be smoke inhalation.
The grisly new details emerged as investigators combed through the charred rubble of the home Monday and released new details about the horrifying climax to a long, bizarre saga.
"This was definitely a deliberate, planned-out event," Pierce County Sheriff's Detective Ed Troyer said.
Investigators found two five-gallon gas cans in the rubble, supporting the theory that Powell, who had lost custody of the boys to his missing wife's parents, had set an accelerated blaze after locking out the social worker who had brought young Charlie and Braden for a supervised visit.
Steve Richards, assistant chief of Graham Fire and Rescue, said responders arrived about three minutes after getting the call and found flames already through the roof.
"It was just devastation," he said.
More details also emerged about Powell's final preparations for his horrific murder-suicide. ABC News obtained what it says was a voicemail Powell left for his family members. In the recording played Tuesday on "Good Morning America," Powell, who had been named a "person of interest" in his wife's disappearance, says he's calling to say goodbye, and that he's sorry to everyone he's hurt.
Jeffrey Bassett, who represented Powell in the custody case, said he received an ominous email from his client just minutes before the fire.
"I'm sorry, goodbye," it read.
Authorities said Powell sent longer emails to some people, including his cousin and pastor, with instructions such as where to find his money and how to shut off his utilities. But none of the emails said anything about what happened to his wife.
Authorities have been investigating the disappearance of Susan Powell as a murder for at least several months, while they publicly left open the possibility that the Utah mother might be found alive.
A search warrant obtained by The Associated Press through a public records request Tuesday shows that police were investigating three felonies in Utah: first-degree murder, kidnapping and obstructing a public servant.
Salt Lake County District Attorney Sim Gill acknowledged for the first time that they believe Powell is dead, saying in an AP interview that the case is being handled as a murder investigation.
The parents of Susan Powell, who went missing in December, 2009, from their Utah home, say the boys were playing happily Sunday and didn't want to visit their father. Charlie and Braden shared a bedroom in the Cox's Puyallup home since last fall, when they were removed from their father's custody.
Charles and Judy Cox tell KIRO-TV that the grandmother talked them into a supervised child custody visit with their father. When the boys arrived at the Graham home where their father moved following the disappearance of his wife, their father barred the social worker from entering and then lit the house on fire.
The Washington Department of Social and Health Services said the social worker is "suffering from grave emotional trauma as a result of the horrific event." Troyer said she did all she could do.
A candlelight vigil was held Sunday night for the boys outside the 7-year-old's school in Puyallup. Chaplains have been counseling the Coxes.
Investigators in Washington are meeting with police from West Valley City, Utah, who have been looking for Susan Powell. The investigation will include a closer looks at Josh Powell's last movements and messages.
Susan Powell, a 28-year-old mother of two, was reported missing Dec. 7, 2009, after she failed to show up for her stockbroker job in Utah.
Authorities in the couple's hometown of West Valley City, about 10 miles outside Salt Lake City, quickly turned their attention to Josh Powell. He was a "person of interest" in the case, but had repeatedly denied any involvement in her disappearance.
"I would never even hurt her," a tearful, red-eyed Josh Powell told CBS' Early Show in August. "People who know me know that I could never hurt Susan."
About a month later, police spent 12 days in the remote central Utah desert looking for clues, and Josh Powell and his father quickly disappeared from the limelight. The search area around Topaz Mountain, a popular spot for rock and gem hunters, was about 30 miles south of where Josh told police he went camping with his two children in the hours before his wife's disappearance -- his steadfast alibi.
On Sunday, the lawyer for Susan Powell's parents, Chuck and Judy Cox, told the AP the children had started talking to their grandparents about things they remembered from the night their mother vanished.
Chuck Cox, who told KCPQ he believes Josh Powell killed his grandsons because authorities investigating Susan Powell's disappearance were zeroing in on him, described a picture that Braden drew at preschool and a conversation he had with the boy.
"In the minivan there was Daddy, Charlie and Braden and then he said, 'Mommy was in the trunk,'" Cox said. "Then he said they had stopped somewhere ... 'Mommy and Daddy got out, and Mommy didn't come back.'"
The Associated Press contributed to this report.