Transcript for An Act of Evil
Move beyond the fringe of Seattle in the shadow of Mount Rainier. Josh Powell is unraveling. It was very -- Very. Also it was very different than Houston. Attorney Steve downing notices the change in court on Wednesday of last week. For Powell -- was to be the next step toward regaining custody of Charlie and Braden. But in this story already full of sexual revelations the most shocking one awaits -- police discover cartoons to. Depicting incest on Josh Powell's computer. And since it is animation and not real children it's not sufficient to arrest him. Not even enough to change his visitation rights. But it is enough for the judge to order that the boys remain with their grandparents. And -- -- -- submit to a Psycho sexual the valuation. Listen very concerning and that was the reason why the court ordered a -- official evaluation. The frustration in this situation as though it seemed. -- -- red flags about Josh Powell. And it makes us wonder why he would get see the kids. And the reason being an initial case plan is reunification. Of children -- their parents. And you know I certainly understand the frustration here. You think you've been broken down he was devastated I think that he -- That the children were beginning to feel safe. With the Cox family comfortable enough to make disclosures. Disclosures that he did not want them to me. Agreement the boys were elaborating on what they told their grandparents about the midnight camping trip the night mommy disappeared. What was coming out of the kids camping with their dad. Having. Their father drive the car that mommy was in that -- In the days following the hearing investigators -- Howell devises a murderous -- -- something he was planning and we can go back as far as at least 24 hour. Pierce county sheriff's detective rich lawyer says Josh visited this shopping complex in the community a few -- -- -- -- from his home. That's him at his bank withdrawing 7000 dollars then. He go shop. We believe that -- -- -- -- from a gas station. And filled up a couple five dollar counter doubts and may be over trip to drive to store purchasing -- bring -- back and set the trap for the kids. Even stops and gives away his -- stores when he made his decision to what is in the bill I don't think anything stop him. And as we just learned tonight he visits a storage locker room. Where a blood stained blanket was later discovered. Sunday morning a few miles away seven year old Charlie and five year old Braden. -- the home of their grandparents chuck and Judy Cox. -- and OK it's time to get ready for your visit and -- -- we don't wanted to see daddy. And they just kept saying that and saw ice OK but it. Daddy wants Cecile he's -- do some fun things don't have a good time -- This sales pigeon shoot program for the rest of her life movement and fortunately we moves. And social -- girl Elizabeth Griffin hall a company Charlie and Braden on their final journey and a ten minute drive to their father's house. -- with me and that high Charlie had things to tell me about school. Meanwhile Josh sends several emails to relatives and acquaintances saying I'm sorry good -- We've moved into the driveway. And I pardons and and they Russians -- -- front door which is what they always did -- excited yet they do have going through this it. Inside the home Josh Powell has just left an anonymous voice message for relatives. People who were available when. They're -- and not be able. To go -- -- I'm sorry everyone I'm -- -- quite. One mile away. Powell's sister Alina is alarmed by the voice mail she's just received. -- -- -- Hands. It is made no sense to me none of it. And it terrified me she calls 911. I think -- -- it is -- traveler. -- -- -- -- And then the media -- Noticed sobbing hearted. I think I tried his cell phone first he didn't answer -- sons and their social worker are at his front door I was one -- two. Steps and back -- them. And the door open. And I and on the kids when he kissed just last stand and by the time I got to the door which was -- -- The door slammed in my faith did you see Josh I side just inside Josh street just 12 his eyes cop mind. And any he had a look in his eyes and this just kind of sheep is -- district is so does that mean like that. And then closed the door and -- slammed the door -- -- denying not to name rang the doorbell and I started its steady yelling at Josh sent me an and I heard him say Charlie I've got a big surprise three you know and then I heard Braden -- out. We don't know -- Josh Powell. Hedging his son's fashions. Panicked by the sounds and the other side of the door. She calls 91 more. -- -- -- And I could not -- -- too many minutes too many too much time I got my. 46 excruciating minutes this skeptical 911 dispatcher is unmoved by Elizabeth's growing sense of alarm. I don't know -- have to respond to emergencies like. -- -- -- I'm not like that why you're wrong with him -- minutes yes. You hang up the phone when you looked at the house where did you realize. I realized that we -- of chapel. Just seconds after making that call -- with law enforcement and root Elizabeth becomes an eyewitness to unspeakable horror. As Josh Powell's house explodes. To a roaring inferno. I couldn't believe that I couldn't believe that -- went screaming into the neighborhoods and had this to children and their these two children in Iraq the -- -- -- -- Because I couldn't imagine those -- those boys. That those parades when my heart. I couldn't imagine for a minute that they -- can -- be in my car again safe for me I mean this can take them home no matter what it's -- -- Checking -- traffic -- -- a spokesman. Richard did what you were supposed to do. I did everything I was supposed to do I did everything I -- everything. I did everything right in the boys there's still death. How could this happen. I eat what I tell myself is how it happened just because stash house was really really he's. Pure evil pure evil. Carrier all the takes a little boys and do it he did there's nothing and describes -- -- to bring the boys and and verbally assault them before lighting them on fire -- his carry him home. For the Cox family for all they lost they also found something here. Because when Josh Powell decided to literally -- himself in hellfire the family took it as a signal. Confirmation. About whom they believe took their daughter. Still leaves -- without -- daughter. And without the voice. So it's a hollow victory. And even one of Josh -- -- sister says she feels the mystery of Susan's disappearance has now been solved. If he was -- to do that had to move voice that he could. Best solo home. To Lewis he went to her. But he had -- -- I don't. Moon. -- the key questions still remain what happened to Susan Powell. If she's dead -- Josh kill her and why. But to Elizabeth those questions now seem almost academic. You have -- overtime. For her the hardest part right now comes down to this tomb empty. -- You have to remember the good stuff that you have a question. But between the tears and the crushing sorrow Elizabeth thinks of Charlie and Braden. Two boys who knew how to be happy even amid the wreckage of their family. The funerals for little Charlie and Braden and Powell take place tomorrow. The caseworker who tried so hard to save them Elizabeth Griffin hall will be there.
This transcript has been automatically generated and may not be 100% accurate.