As an adult, Josh appears to have repeated in his own marriage to Susan Cox Powell some of the same emotionally abusive behavior he witnessed growing up even as he sought to distance himself from his father's control by moving from Washington to Utah with his new wife.
In the years following his parents' divorce Josh repaired a frayed relationship with his mother. Last year, she defended him as a loving, caring father as he sought to regain custody of his sons from the state.
But Steve and Terrica Powell's troubled relationship, acrimonious divorce and his father's behavior may have left a lasting mark on their oldest son.
"A child living within the family dynamics described in the divorce filings often tries to appease a parent who terrifies them by, usually subconsciously, adopting their beliefs and thought patterns," said David Reiss, a California psychiatrist and expert in character and personality dynamics.
"On some level, the child is going to align himself with the person he sees as a threat," Reiss said.
A child learns safety depends on a parent's moods rather than his or her own behavior.
"They get into a view of the world where emotions define reality instead of logic," Reiss said.
And while the violence that unfolded here nearly a week ago is hard to predict, the most reliable predictor is previous violence and Josh's childhood history placed him in that statistically higher risk group, Reiss said.
"The vast majority of people who have horrible childhoods don't go on to do what he did, but you can surely point to vulnerabilities," Reiss said. "You can provide information about why someone develops a lack of morals or logic, but why someone acts in that way is unfathomable. That's just the horror of it. It is absolutely senseless."
The Salt Lake Tribune attempted to speak with several of Josh's siblings who supported him following his wife's disappearance, but they declined interviews as has Josh's mother in the past. His uncle and aunt also declined comment through their daughter.
The divorce of Steve and Terrica Powell involved allegations of mental unfitness, pornography, polygamy and even witchcraft. There were serious conflicts over religion and parenting, and a tug-of-war ensued over the children, who at the time ranged in age from 18 to 7. Josh, the second oldest child, was 16.
Steve eventually was given custody of the three boys, while Terrica had custody of Alina, their youngest daughter though within a couple years she also went to live with her father.
In 1992 court filings, Steve claimed his wife, who studied herbs and natural healing, had mixed a New Age mysticism with Mormon beliefs in a way that amounted to practicing "witch craft and devil worship."
Terrica responded that it was Steve who collected books on the occult and claimed his interest in pornography, which he had shared with their sons, had corrupted him.
"A huge part of that case involved the pornographic interest of Steven Powell and the impact it was having on the children," said Tacoma attorney Steve Downing, who represents Powell's in-laws Chuck and Judy Cox.
Steve was arrested last September on charges of voyeurism and child pornography based on images police found during a search of his Puyallup home, a home which he then shared with Josh and his grandsons. That's when the state took custody of the boys and placed them with their maternal grandparents, Chuck and Judy Cox.
In an initial custody hearing, Josh said he was unaware of his father's interest in pornography.
"For Josh Powell to sit in court and claim he knew nothing about his father's pornographic interests was somewhat stunning since it is so much a part of the 1994 divorce case when he was 15 and 16 years of age," Downing said.
In the divorce filings, Terrica told the court she believed her husband needed "serious medical help" due to some "underlying problem," perhaps stemming from his childhood.
Steve and three siblings were taken by paternal grandparents and kept for a year before being reunited with their mother, whom they were told they'd never see again. The experience was "very damaging," Terrica wrote.
She thought their older boys would benefit from counseling, too, to "undo that faulty thinking that he has established in them."
The couple were members of The Church of Jesus Christ of Latter-day Saints when they married, but Steve had become disillusioned with the faith and it became a flashpoint in the marriage a pattern later repeated in Josh's own marriage.
Like his parents, Josh and Susan married in an LDS temple; like his father, Josh later became disaffected from the faith.
At one point, Terrica said, Steve proclaimed he had a "right" to take another wife and had his eye on a woman who was already married, writing a song about her and detailing sexual fantasies in his journal.
Steve's parenting was equally off-base, Terrica told the court. Her husband would ignore certain behaviors of their children and then suddenly turn on them "far more violently than was necessary or fair," which would result in yelling, name calling and spankings that were too forceful and too long.
Steve subjected Josh in particular to this contradictory, overly harsh discipline, she said.
"For years, he pointedly attacked Josh very frequently, nearly every day for a time," she wrote.
Steve acknowledged Josh was a challenge.
"At times I have no idea how to handle Josh," he wrote. "He is very independent, and he is now a little taller than I, and may, with his regular weight-lifting, be a little stronger and bulkier than I. I cannot spank him. Spanking didn't even help when he was younger."
Terrica said Josh had become withdrawn as a teenager, "unwilling to interact, even to make eye contact for a year or two. He seemed to have a soul-deep hurt because of his dad's erratic and explosive behavior."
When he was 13 or 14, Josh tried to commit suicide by hanging himself.
Terrica said she believed her son's difficulties were due to "not knowing where the boundaries are what are the limits of acceptable behavior."
And for that, she blamed her husband Steve.
Carol Martin, Terrica's mother, described her son-in-law as having grown "very anti-church, anti-country, anti-authority, anti-morality, very radical" over the course of their marriage.
"All the while [Steve's] teaching the boys these things," Carol Martin wrote to the court. "He has taught the boys to mock and insult their mother, as he does."
Terrica claimed her husband steadily turned their sons against her, dividing the family.
"There have been times when I have been afraid of Steve and/or the boys because of their extremely hateful behavior," Terrica wrote. "They group together and stir each other up to almost a fever pitch at times. Their vehemence has often flashed in their eyes and body language, making me feel threatened."
When she had asked Josh once to show her more respect, he had responded by saying, "You have to earn respect, mom. What have you done to earn my respect?"
Worse, Terrica said Josh and his younger brother John, then 15, had at times pushed and hit her.
Once, when she had tried to get Josh to do his dishes, he had turned to her, a butcher knife in his hand, and in a menacing way told her, "Don't push it, mom."
Becky Mulcahy, Terrica's sister, was visiting at the time, observed that the older boys had a "very distorted image of their own unquestionable right to do anything they darn well please . . . combined with a very deep contempt towards women in general and any authority at all" all encouraged by their father.
Jennifer Powell Graves, then 18, submitted a letter to the court recounting a discussion with her father prompted by a newspaper article about men who stalk or kill former lovers.
"I asked him if he'd do that to mom if she left him," Jennifer said. "He said, 'I'd like to think I wouldn't go that far.'"
Jim Martin, Terrica's brother, said he had had a close relationship with Steve but had become troubled by the way he often undermined Terrica when she told the children to do something.
"As a father of five children myself, it terrifies me to watch his children learning the things they are," Jim Martin wrote.
Shortly after Susan Cox Powell's disappearance in December 2009, close friends observed that Josh, was "very, very controlling" and often attempted to "undo" whatever his wife asked of their sons.
Susan would put the boys to bed, and Josh would get them up again, saying such things as, "Mommy is so mean." Their marriage was on the brink of collapsing, just as his parents had 20 years earlier.
Back then, Terrica said that Josh at times "shows a very sweet side," but she felt her husband's influence had been so detrimental that it would be best if the two older boys were placed with relatives.
""With the kind of disrespect the kids have learned to have regarding laws, I worry about what they will do," Terrica wrote. "It seems like there is a sickness pervading my family and I have been powerless to stop it.""