That startling information came from the results of an autopsy that determined Charlie and Braden Powell died from carbon monoxide poisoning. But 5-year-old Braden also suffered "chop injuries" to his head and neck. His 7-year-old brother, Charlie, suffered a chop injury to his neck, acording to Melissa Baker, an investigator with the Pierce County Medical Examiner's Office.
Josh Powell's death was listed as a suicide. His sons' deaths were listed as homicides.
The autopsy results were the most shocking in a day of revelations: Powell used 10 gallons of gasoline to ignite the fire; e-mails were sent not just to his attorney, but to friends and family foreshadowing his plans; the children's toys were given away by Powell before his children's arrival, and the head of the West Valley police department came to Washington vowing to press on in the search for Susan Powell to give closure to the children's grandparents, Chuck and Judy Cox.
In addition, Pierce County officials are now calling Josh's father Stephen Powell a person interest in the case.
On Monday, Chuck Cox recalled going into his grandsons' bedroom Saturday night to find them both "curled up in their beds sleeping peacefully."
Braden was tucked into his bed with pillow sheets from the Disney movie "Cars." Charlie was sleeping underneath a Spiderman themed bedspread. The boys were worn out after a day of watching their older cousin play basketball and then playing in their grandparents' large backyard full of dirt piles, trees and lots of mud and water.
Sunday morning, the boys had a breakfast of fruit and cereal. Then Chuck Cox went off to a church function. The boys, who were not allowed to attend services or be influenced by the LDS Church at the insistence of their father, Josh Powell, were picked up at 11:30AM to be taken to their father's home for one of their weekly three-hour supervised visits.
Now, Cox says it's too painful to have those beds in his house.
"I'm going to have to take them down. I can't have them here," he said Monday.
Sunday at breakfast was the last time Cox saw his two grandchildren.
"Very, very quite shocking. We had no idea it was going to end in this way for these boys. We had made plans to take care of them," Cox said Monday at his Puyallup home. "I couldn't believe it's happening."
Cox was able to keep his composure for the most part on Monday as he accommodated numerous media requests for interviews. But at times, he fought back tears as he recalled his last days with Braden and Charlie.
"We knew we were not going to bring Susan back, but we were hoping to at least give the boys a chance at a good life. And now that's been taken away by their father killing them."
The sad reflections were shared Monday, a day after police said Josh Powell took two 5-gallon cans filled with gasoline into his house in the sleepy town of Graham, Washington at 8119 189th Street Court East.
"One (can) was found with the bodies. The other one, we believe, was spread throughout the house. There were accelerants throughout the entire house," Pierce County Sheriff's Sgt. Ed Troyer said.
Investigators combed through the rubble of Powell's house Monday. They believe the fire started somewhere near the center of the home and was set immediately after the children were taken to the house by a court-appointed supervisor.
"He (Powell) pushed her out. He blocked her out," Pierce County sheriff's spokesman Ed Troyer said of the supervisor. "The whole thing was planned."
The social worker called her supervisors to report that she could smell gas, and moments later the home erupted in flames.
Just before 6:00PM Monday, investigators announced they were done with the house and turned the property over to an insurance company. A chain link fence was then constructed around the property with yellow police tape warning against trespassing.
Neighbors and curious onlookers began creating a makeshift memorial for the boys, leaving balloons, flowers and stuffed animals outside the fence.
"Pretty much devastation, not much left," Steve Richards, Graham Fire and Rescue's assistant chief, said of the scene earlier Monday as the investigation was starting. "We're going to try to put the pieces of the puzzle together."
The first firefighters arrived just three minutes after receiving the call. The nearest fire station is only one block away from Powell's home.
"Upon our arrival, the fire was burning hot," Richards said. "It was heavily involved, fire through the roof."
Patrick and Necia Small rented the house to Powell last fall.
"My concern was who he was. But I figured they had not convicted the man. He was due a second chance," Necia Small said Monday. "Our main concern (now) is the family."
Police said Monday that Powell sent multiple emails just minutes before the fire to people like his pastor, relatives and his attorney. Some of them simply said, "I'm sorry, goodbye." Others dictated what he wanted people to do with his money, utilities and "certain aspects of his life," Troyer said.
"None of these emails arrived anywhere where anyone could do anything about it, but they do show that he was intending to do this before this occurred and he planned this event out," he said. "This is something he planned on doing no matter who was hurt."
None of the emails talked about his missing wife, Susan Cox Powell.
Family members — and many others who have been following the high-profile case — continued to struggle Monday to understand what went wrong.
"This isn't fair he had to be such a jerk and take them away with him," an emotional Denise Cox said in tears. She was reflective, angry and numb late Sunday as she stood at a candlelight vigil at the elementary school of her two nephews. "It's not fair that everybody has been taken away from our family,"
At the Cox house on Monday, even the smallest objects reminded Chuck and Judy Cox of their grandchildren.
Before talking to reporters. Chuck Cox spotted a small bowl with small balls of dirt and clay.
"Charlie thought it was like gold to him," he said.
Braden inherited his mother's energy and mischief while Charlie got his mother's artistic talents, the Coxes said. Next to his bed, a plastic container with "Charlie" written across the lid housed his art supplies. Taped to the window of the boy's bedroom was a snowman and snowflakes Charlie had cut out of paper.
As Chuck Cox went through the boys' room Monday, he showed the two boxes of toys filled with matchbox cars, a Magic 8 ball that given as a gift to the boys and a stuffed Angry Bird.
The toys will be donated to local nurseries, schools and charities, he said.
Josh Powell also donated boxes of his boys' toys and books to a Goodwill charity over the weekend before his children arrived, further evidence that he planned to kill his children.
When asked whether he ever suspected his son-in-law would take the lives of his own children, Cox said no.
"We suspected that if he had the boys in his control with him, living with him, and he felt the police were closing in on him, that he was capable of killing himself and the children. But we thought we were safe. We had control of the children. The visits were supervised," he said.
"He's disturbed. The act he did was cowardly, a desperate act. And he murdered the two grandchildren, two innocent grandchildren.
"And I don't know what he did to my daughter, I don't know how, but I know he's responsible for her being gone. ... I cannot stand the sight of him."
The Coxes do not believe the mystery of what happened to their daughter died with Josh Powell. They said his father, Steven Powell, who is currently incarcerated at the Pierce County Jail on charges of voyeurism and child pornography, knows something about what happened.
West Valley's police chief agrees.
Speaking Monday in front of Powell's burned out house, an emotional Buzz Nielsen said he hopes now that Josh Powell is gone, someone who knows something about what happened to Susan will step forward..
"I told the Coxes I won't give up. I'm still not," he said.
Nielsen said the decision by Powell to take his life was his own had nothing to do with the investigation by West Valley police.
"Where we are in the criminal case, Josh didn't know about it," he said.
Nielsen would only say Monday that his department is "making progress" in the case of Susan Powell's disappearance. "I was optimistic."
Nielsen said he traveled to Washington to personally meet in private with Chuck Cox. He became emotional when talking about the Coxes' grandchildren, showing the personal investment he has had in the case.
"After 30 years … this is right there with the worst you would ever imagine," he said of the crime scene.
Ultimately, Chuck Cox said he had hoped to gain permanent custody of the two boys and then have Josh's sister, Jennifer Graves, and her husband adopt them. The couple lives in Utah.
Cox said he does not blame the state for what happened, saying theycases workers performed within the structure of the law. But he said he did not like that Josh Powell was allowed visitation at his own home and with only one supervisor.
"We wished they weren't at his house. And we didn't like the fact there was one supervisor there to watch and quite frankly, she couldn't have stopped him if he'd wanted to do something or drive off with the kids or something like that," he said.
The breaking point for Josh Powell, Cox believes, was last week's court hearing in which a judge ordered the Coxes to retain custody of the children and also ordered Powell to undergo a psychosexual evaluation.
"He lost control of the children. He was sure he was going to get them back by just claiming to take care of the issues … When he realized he really didn't, and those pictures came out from his computer … I think that was it. He knew that it was over," Cox said.
It was losing control of the situation that likely sent Powell over the edge, Cox said.
"They were his property and he wanted them back. They were his. And that's all it was. He wasn't really interested in them," he said. "I believe that he knew it was coming down to the point that his stories, his wild accusations and stuff, he was going to have to answer to them and come with facts and he didn't have any facts, and so he saw no way out."
Cox talked about a picture Braden drew when he was 2 during a preschool summer camp. In the picture, he, his brother and father were in a car going on a camping trip. When counselors asked him where their mother was, he told them: "In the trunk." When they asked why, he said he didn't know, Cox said.
Chuck and Judy Cox said they will fondly remember the four months they got to spend with their grandchildren. When the boys first arrived at their home, they were "very disconnected from emotion, they were like little robots and if you talked about Mommy, they would run away."
But during the last week of their lives, "I could not be sitting down without them climbing up in my lap and wanting to be on me, hugging me or being held by me," Chuck Cox said.
"We know the children are with their mother and they're safe. ... They're innocent children, they were killed by their father, and they're back with their mother right now. We believe we'll see her again after this life, so our faith keeps us where we have hope."
But both Chuck and Judy Cox said they won't have complete closure until their daughter's body is found.
"To find Susan and put everything together, and then we feel we can truly heal," Judy Cox said.
Monday at Emma L. Carson Elementary, where Charlie was a first grader, teachers and administrators were briefed about his death before school began.
"It's very sad here," said Karen Hansen, executive director of communications for the Puyallup School District.
Teachers and staff at the school were offered counseling before classes began Monday. They were also given a list of ideas about how best to address the sensitive topic with students.
A handout suggested telling students: "I have sad news to report. Yesterday, Charlie Powell, one of our fist grade students, died in a terrible tragedy. He was a nice friendly young man and our Carson family will miss him."
Hansen said guidance counselors were also present and teachers planned to be "very vigilant" about watching children for any signs that may warrant help.
Steven Powell remained in the Pierce County Jail Sunday on voyeurism and child pornography charges. He reportedly was placed on a suicide watch. Troyer said he denied all media requests Monday for interviews.
At the home of Steven Powell, where Josh's sister and brother still live, there were three vehicles in the driveway Monday afternoon, but all the blinds in the house were drawn and no one answered the door.