The Agony of Peter Rodger, a Dad Whose Son Became a Mass Killer

— -- It was in the parking lot of a Home Depot in Isla Vista, Calif., that Peter Rodger would learn that his 22-year-old son Elliot was dead.

"I'll remember this forever the rest of my life," Rodger said. "The way [the sheriff] just looked me in the eye, and he said, 'We've found a deceased person and we found a license in his pocket that fits your son's description.'"

Elliot's mother, Li Chin Rodger, and Peter's current wife, Soumaya Akaaboune, both protested to the police. "No, no, no, no, he's not dead," they pleaded.

"Can somebody clarify this to me?" Peter Rodger asked in the confusion.

The sheriff gave the same cold answer. "We've found a deceased person, and we found a license in his pocket that fits your son's description." It was that moment Peter Rodger realized that his son was actually gone.

What he didn't know yet was that his son was a mass murderer, that Elliot had used knives, handguns and his car to murder six people and injure 13 near the UC-Santa Barbara campus before taking his own life. The carnage caused by his son transfixed that nation on May 23 as his fury left a trail of blood through the campus town.

Read Peter Rodger's Open Letter: "We Have to Try and Stop This"

How to Spot Signs of Mental Illness and Ask for Help

Earlier that evening, Peter Rodger had been enjoying dinner with friends at his home a hundred miles south in Los Angeles. He had received an e-mail from his son. Elliot's mother received the same email which contained a menacing 137-page diary addressed to his parents, life coach, and others entitled "My Twisted World."

Li Chin had Googled her son's name and found something even more chilling — a YouTube video called "Elliot Rodger's Retribution." It showed her son sitting in the driver's seat of his black BMW — a car which he would turn into a deadly weapon — spewing a hate-filled, sexist tirade.

Before Peter Rodger could read the e-mail he received a desperate phone call from Chin. "You've got to go on YouTube," she implored, sending him the link.

"I just went to the YouTube page and saw, the retribution video," he said with a sigh. Watching his son say such terrible things, Peter Rodger said he remembers a wave of darkness washing over him. "A really dark force of horrible energy hit me."

That was the beginning of a nightmare that won't end for Peter Rodger as he continually relives the moments of his son's life, from the happy days when Elliot was a laughing little boy to his increasingly dark world. He recalls with a twinge of regret the what-could-have-been moment when Elliot's alarmed mother called police on her son, but they left after Elliot convinced them that his online rantings were harmless. At that point Elliot had already purchased three guns and had been practicing at a firing range in preparation for his "retribution."

Peter Rodger said he does not blame the police, but would like to see the law changed so that gun checks are required on these types of calls. "If they did do a gun check, they would know that Elliot had bought three automatic weapons. They would have the right to seize him for 24 hours, and his whole scheme would've been over and thwarted," he said in an exclusive interview with ABC's Barbara Walters.

Although Peter Rodger had watched his son's video that night, it was three weeks before he could bring himself to read his son's manifesto. The document was an extension of what Elliot had declared on YouTube. He detailed his childhood, family problems, his inability to get a girlfriend, and his hatred of women, ethnic minorities and interracial couples. And it contained his plans for a massacre.

Peter knew that his son had been writing, though Elliot had refused to share what he was writing about. On a hike with his son sometime before the killing spree, Peter Rodger asked, "'Can I please read it? Can you please just send it to me?' And he said, 'Oh, no, no, no. I'll send it to you soon enough.' I had no idea it was this."

His father said he never believed that his son would have done something like this, despite the years of therapy.

"Elliot was far from evil. Something happened to him. He was the most beautiful, kind, sweetheart of a boy. And something happened to him," Peter Rodger said. "He was adorable. And he would laugh so much that sometimes we were worried he would choke," he told Walters.

Elliot Rodger was born in London to Peter Rodger and Li Chin, a Malaysian-born nurse who had worked as a unit nurse on the set of "Indiana Jones and the Last Crusade." Peter also worked in film, directing television commercials and working on the hit film "Hunger Games."

At the age of 5, Peter, Chin, Elliot and his little sister Georgia moved back to California. Those were the good years. "It was really wondrous, those first four, five years of his life. It was wondrous. He was a really adorable, cute little boy," Peter Rodger said.

When Elliot was 7, Peter and Chin divorced. A year later, Peter remarried, this time to Soumaya Akaaboune, a Moroccan actress who had appeared in the Hollywood blockbuster "Green Zone."

It was also the year Elliot began his long journey with therapy.

"My little 9-year-old self realized that there were hierarchies, that some people were better than others. Jealousy and envy…those are two feelings that would dominate my entire life and bring me immense pain," Elliot wrote.

But Elliot hid that pain well, his father claims.

"If he were sitting here right now, you would think, 'What a polite boy he was,'" Peter Rodger said. "But yet, he had this thing going on inside of him."

Peter Rodger said he never had an inkling that his son harbored a lethal rage inside him.

"There's no way I thought that this boy could hurt a flea. He'd never, ever been violent or showed any violent tendencies ever, ever," he said.

"I think that his mind was taken over by a disease," his father has concluded.

The lonely young boy had become an introverted teenager. By the age of 13, Elliot had walled himself into the fictional cyberworld of "World of Warcraft." His constant companions were the heroes and villains of the online fantasy game.

In high school, Elliot was bullied, though his father said Elliot would never talk about it with him. There were incidents when food was thrown at him, incidents when he was pushed into lockers. "I was an innocent, scared little boy trapped in a jungle full of malicious predators, and I was shown no mercy," he later wrote in his diary.

He would leave two high schools before landing at the tiny 100-student Independence High.

For all the things that Elliot had — the Black BMW, the designer sunglasses — there was one thing that always eluded him: a girlfriend. And that became his obsession until the very end. "I mean look at me, I'm gorgeous. But you girls don't see it. I don't understand why you're so repulsed by me," Elliot stated in his retribution video before his killing spree.

The campus of the University of California at Santa Barbara sits right along the Pacific Ocean. The skies are blue and clear more days of the year here than not, and Elliot's parents thought the sunshine and college life would help their introverted son grow up. Elliot attended the nearby Santa Barbara City College, but had stopped attending classes this year.

"I thought that by putting him out there and giving him independence and integrating him into a normal society would very quickly help develop the skills that I thought was lacking in him," his father said.

But it was at college that Elliot would begin planning his day of retribution. "It was only when I first moved to Santa Barbara that I started considering the possibility of having to carry out a violent act of revenge, as the final solution to dealing with all the injustices I've had to face at the hands of women and society."

His fury towards women drew him to misogynistic websites. In one online forum he wrote, "start envisioning a world where women fear you."

After not hearing from her son for a couple of days in April, Elliot's mother Li Chin became nervous. Intuitively, Peter Rodger said, she began sniffing around on the internet to see if there had been an accident. What she found was Elliot's YouTube account.

Elliot had been uploading bizarre videos to YouTube, although none contained a specific threat. Knowing that Elliot would never consent to a "mental assessment," Chin called her son's life coach who called the Santa Barbara District mental health hotline. The hotline alerted police and asked them to make a welfare check on Elliot, which prompted six officers to show up at Elliot's door.

"Elliot was a very, very polite, kind, well-spoken, well-dressed individual," his father said. "And he managed to say, 'You've got nothing to worry about.'" The police left without taking any action or running a gun check.

On that day in May, that Memorial Day weekend, Elliot Rodger would kill seven people including himself, wounding 13 others.

"I don't understand it. I can't wrap my head around it," said Peter Rodger. "It will haunt me, haunt me for the rest of my life."

Elliot's mother has declined to discuss her son or the tragedy of last May.

"I feel the world's attention should be focused on the victims' loved ones and remembering the beautiful lives that were so tragically lost," she said in a statement to ABC News.