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On the surface Josh seemed like a devoted dad, but after he killed his two sons in a horrific murder-suicide, new details about his dark past are starting to emerge.

Josh Powell stunned the world when he killed himself and his two sons in a fiery explosion. Now details about his troubled history — such as holding a knife to his own mom and the discovery of shocking incestuous porn on his computer — are coming out. “I believe that he understood that there was no way he was going to bluff his way through this, not with the lie detector test on top of the examination, and that this was it,” Josh’s father-in-law Chuck Cox tells The Today Show. “The truth was going to come out.”

Josh had a VERY troubled past: He attempted suicide as a teenager, threatened to kill his mother with a butcher knife and murdered his sister’s hamster by smashing it against its cage! In 2009, police found animated pornography of adults and kids having sex.

Chuck admitted he hadn’t heard about the disturbing images until it was just reported on The Today Show. He says that if he and his lawyers had known about it, the family might have been able to limit Josh’s visitation rights sooner.

“I think everybody underestimated what he was capable of,” Chuck says. “I could not believe he would have taken a hatchet to his own children… This is just such a strange twist.”

Now it’s clear the murder-suicide was premeditated. The day before the explosion a security camera caught him withdrawing money from his bank and buying gas cans. He gave away his boys’ clothes and toys and dumped something secret at a landfill.

The family have moved the memorial for the boys to a larger venue, will stream it on the internet and are allowing TV cameras there.

“It’s clear that people all over the world are affected by this horrendous act and care about our grandsons,” explains Chuck. “We want to share with them and allow some other people to have closure on that part of it. So we felt it would be only right to allow other people the ability to grieve and to take part in a memorial service.”

Such a SAD story! Are you shocked by Josh’s past behavior? Do you think he should have lost custody sooner?