Josh Powell's Final Message: 'I Am Not Able to Live Without My Sons'

Feb. 7, 2012— -- As investigators pore over the gutted Washington state home of Josh Powell for evidence explaining how and why he murdered his two sons and killed himself in a gas explosion, ABC News has exclusively obtained what is believed to be his final words to his loved ones.

Powell left a voicemail for his family just 20 minutes before attacking his two young boys Braden, 5, and Charles, 7, with a hatchet and igniting a gas leak that blew up his house on Sunday afternoon.

"I am not able to live without my sons, and I'm not able to go on anymore. I'm sorry to everyone I've hurt. Goodbye," the voicemail message said.

Many are now looking at the tumultuous relationship that Josh Powell had with his father Steven Powell, whose September arrest led to charges of 14 counts of voyeurism and one count of child pornography. The pornographic images were kept in the home the two men shared with Josh and Susan's boys – a fact which led to Josh Powell losing full custody of his sons.

The boys were ordered in a Washington court in September to remain in the custody of Susan Powell's parents Chuck and Judy Cox because they had been living in a dangerous home environment with sexually explicit material, and because of the possibility that Josh Powell participated in the voyeurism and child pornography charges against his father.

Steven Powell has now been named a person of interest in the disappearance of Susan Powell, according to Seattle's Q13 FOX News, which reports that he was not overly emotional when he heard the news of the explosion, and has been uncooperative with Pierce County deputies. He is currently on suicide watch.

John Hallewell, who was Josh Powell's best friend, says that Sunday's murder/suicide was likely not done as revenge against his missing wife because "all he ever thought about was himself."

"Josh has his problems, but he was trying to do what was right and start a family and do all those things … I think especially once Josh moved to live with his father, and he just got a hold of him, and basically he went downhill pretty fast from there," Hallewell told ABC News.

"I don't think it could have been for revenge," Hallewell added. "I think it was more a case where he thought he was in a corner and didn't have a way of keeping the kids, and thought if I can't have them nobody's going to. I don't think he even thinks enough about anyone else to do it for revenge."

Reacting to the voicemail Tuesday Alina Powell, Josh Powell's sister, released a statement.

"Josh and his boys spent more than two years being crushed alive by hate, harassment, and abuse. None of us could have anticipated the devastating tragedy that took place Sunday, but what this unimaginable loss shows is that hate will never end well," Alina Powell said in the statement. "Hate kills."

Powells Moved to Utah to Escape Father

In addition to finding voyeuristic images of two of Steven Powell's neighbors on the 61-year-old's hard drive, investigators found images of his own daughter-in-law, Susan, who went missing in December of 2009 under bizarre circumstances.

In a September 2011 interview with "Good Morning America, Steven Powell said that he was in love with his son's 28-year-old wife, and that his son was fine with that.

Police in Washington say that's simply not true. Sgt. Ed Troyer, Pierce County sheriff's spokesman called these statements fabrications.

"Everything he's saying about Susan and him having any type of relationship is a flat-out lie. She didn't like him, [she] thought he was a creep and weird," Troyer said.

Susan Powell's friends say she told them her concerns about Steven Powell were a major factor in the family's decision to move to Utah in the first place—to raise their children far away from her father-in-law.

"When I first met Josh they had just moved from Washington to Utah, and they were trying to get away from the influence of Josh's dad," Hallewell told ABC News adding that Susan had told him that Steven Powell would never be allowed to set foot in her house.

Just last week, in the latest of an ongoing custody battle between himself and Susan's parents Chuck and Judy Cox, Josh Powell made a declaration to the court that he was the best and safest person to be raising his two sons, saying he had proven to be "a fit and loving father."

Days later, he had donated the boys' belongings to Goodwill, seemingly preparing to murder the family he told ABC News in August he would always protect.

"The people who know me know that I'm a good dad," Powell told "GMA" in August. "I work hard. I put my sons first. I was a good husband. I took care of my family."

Stay with ABC News for continuing coverage of the Powell case and watch "Sins of the Father" on "20/20" Friday at 10 p.m. ET for an in-depth look at this family tragedy.