Law enforcement authorities load a body onto a vehicle following an explosion at a house in Graham
In an apparent murder/suicide Josh Powell, the husband of missing Utah woman Susan Powell, allegedly ignited a gas leak in his own home, killing him and his two children on Sunday. A DA has said he believes Susan Powell is dead. Authorities have been investigating her case as a likely murder, according to a report. REUTERS/Chris Goodenow

Josh Powell, the husband of missing Utah woman Susan Powell, is accused of causing the explosion that took his life and that of his two young sons on Sunday. Authorities have told the media that they believe the huge explosion at Josh Powell's Washington state home was done intentionally and that the case is a double murder-suicide.

Everything we know right now, this has become a crime scene, Graham Fire and Rescue Chief Gary Franz told the media.

Several events happened years, months and weeks before the explosion at Josh Powell's house provided a tragic end to the life of the man who was considered a person of interest in the case about the disappearance of his 28-year-old wife.

Below is a breakdown of what happened, leading up to Sunday's explosion.

-- The explosion at Josh Powell's house happened just moments after a Child Protective Services worker brought the two boys -- Charles, 7, and Braden, 5 -- for a supervised visit, Franz told media.

-- Josh Powell let the two boys in the house, but refused entry to the social worker.

-- The social worker smelled gas and called her supervisors to report the smell and the home exploded.

-- Authorities heard of the explosion in Puyallup, Wash., around 12:15 p.m. (3:15 p.m. ET), Pierce County Sheriff's Department spokesman Ed Troyer told the media.

-- The fire was still burning some four hours later and by 7 p.m., the bodies were said to be recovered.

-- Troyer told the media that the sheriff's department has copies of an e-mail that went to Powell's family and friends, which states that he couldn't live with what was going on, authorities said. Authorities haven't confirmed whether the message did come from from Josh Powell, but have said they have no reason to believe it wasn't from him.

-- Josh Powell's lawyer told The AP that he received a three-word e-mail from the father stating, I'm sorry, goodbye.

-- The boys were living with Susan Powell's parents because Josh Powell's father, Steven, was arrested on child pornography and voyeurism charges last fall.

-- A judge denied Josh Powell's attempt to regain custody, of the boys last week, stating that he should undergo a psycho-sexual evaluation before she makes that consideration.

-- Josh Powell was under investigation in connection with his wife, Susan's, 2009 disappearance from their West Valley City, Utah, home. Josh Powell said he took the boys out during that snowy night and returned home to find his wife was gone.

-- Last year, when Josh Powell's father was arrested on 14 counts of voyeurism and one count of possessing child pornography charges, Josh Powell was living at his father's house and so a judge gave Susan Powell's parents custody of the two boys.

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