It was the 1960s. Ben Carson, 14-year-old ninth grader, was growing up rough in Detroit. And, one fateful day, the future neurosurgeon and Republican presidential contender got very, very angry.

The argument, like many among teenagers, was about nothing: what radio station to listen to. Carson’s friend Bob dared turn the dial on the transistor radio.

“You call that music?” Bob said.

“It’s better than what you like!” Carson yelled back, grabbing for the dial.

That could have been it — good friends have argued about greater things and quickly made up. But Carson found himself consumed by rage.

“In that instant blind anger – pathological anger – took possession of me,” he wrote in “Gifted Hands,” his 1990 biography. “Grabbing the camping knife I carried in my back pocket, I snapped it open and lunged for the boy who had been my friend. With all the power of my young muscles, I thrust the knife toward his belly. The knife hit his big, heavy ROTC buckle with such force that the blade snapped and dropped to the ground.”

His friend — and his own future — saved by a belt buckle, Carson said the incident led him to get his temper under control with the help of god.

Washington Post nonfiction book critic Carlos Lozada recently binge read eight of Donald Trump’s books and five of Ben Carson’s. (Tom LeGro/The Washington Post)

“I stared at the broken blade and went weak,” Carson wrote. “I had almost killed him. I had almost killed my friend.”

The knife story — along with tales of how Carson punched someone, threw rocks and tried to hit his mother with a hammer — are essential stops on Carson’s road to redemption that makes him such an appealing candidate to some. The knife even made its way into a TV movie about Carson. But now CNN, which mounted an investigation of the story, claims it cannot find Carson’s purported victim — and the candidate himself has said the names he used in this tale and another from his reportedly violent past were “fictitious.”

“I don’t like to generally bring them in,” Carson said to reporters Thursday in Fort Lauderdale, Fla. “The names I used for instance are fictitious names because I don’t want to bring people into something like this because I know what you guys do to their lives‎.” He added: “I’m not going to expose them.”

In an interview with Fox Thursday night, Carson explained why. In this interview, “Bob” became “a close relative.”

“The person that I tried to stab, you know, I talked to today,” Carson said. “… They were not anxious to be revealed. It was a close relative of mine, and I didn’t want to put their lives under the spotlight.” He added: “Do you think I’m a pathological liar like CNN does?”

But CNN said this wasn’t just a matter of pseudonymous sourcing. The network said it talked to 10 people who should have known about Carson’s temper — and they didn’t remember it. The network also said it approached the Carson campaign for more information, and the campaign wouldn’t provide it.

“We went out to find these people in Detroit,” CNN reporter Maeve Reston said. “We went through the yearbooks. We called many of his classmates. We found his close friends through every period of his life. And the person that he describes in these anecdotes on the campaign trail as leading up to this religious epiphany that he had cannot remember any episodes of violence involving Dr. Carson.”

The people CNN talked to didn’t challenge the stories. But the Carson depicted in the candidate’s books isn’t the Carson they knew.

“I don’t know nothing about that,” Gerald Ware, a high-school classmate CNN interviewed, said of Carson’s purported outbursts. “It would have been all over the whole school.”

“They describe him as meek, quiet,” Reston said. “You know, someone who would never defy his mother’s order to cross the street. And so it’s really just raised a lot of questions about these stories.”

A 17-year-old video surfaced of Republican candidate Ben Carson claiming that the Biblical figure Joseph built the Egyptian pyramids to store food. The Fix's Chris Cillizza explains why this comment will only help Carson's campaign. (Sarah Parnass/The Washington Post)

In another incident Carson wrote about in “Gifted Hands,” Carson said he and a classmate came to blows after the classmate taunted him for a wrong answer he gave in seventh grade English class.

“Jerry shoved me,” he wrote. “I stumbled, and my temper flared. I forgot the 20 pounds of muscle he had on me. I didn’t see the kids and teachers milling in the hall. I swung at him, lock in hand. The blow slammed into his forehead, and he groaned, staggering backward, blood seeping from a three-inch gash.”

After the principal intervened, Carson apologized.

“I was ashamed,” he wrote. “Christians didn’t lose their temper like that. I apologized to Jerry and the incident was closed.”

CNN, however, said it couldn’t find Jerry.

“We still are looking for this Jerry and Bob that he’s described,” reporter Reston said. “But we’ve contacted all of the Jerrys and Bobs that we could in his class, and still have not been able to find anyone who was part of these incidents or who was involved in them, and we’ve not been able to find any eyewitnesses to them, either.”

See photos of Ben Carson on the campaign trail

SPARTANBURG, SC - FEBRUARY 20: Republican presidential candidate Dr. Ben Carson walks around greeting people at the Beacon Drive-In restaurant on the day of the South Carolina Republican presidential primary in Spartanburg, SC on Saturday Feb. 20, 2016. (Jabin Botsford/The Washington Post)

Carson thought this bit of sleuthing wrong-headed.

“‎Why would anybody know about, you know, private incidents like that?” he told CNN. “You know, I was generally a nice person, it’s just that I had a very bad temper. … So unless you were the victim of that temper, why would you know? Just because you happened to know me? That doesn’t make any sense.”

Besides, was Carson — 64 years old and in the middle of a presidential primary — really being asked about Jerry-whose-name-isn’t-really-Jerry and Bob-whose-name-isn’t-really-Bob and what they saw more than 50 years ago?

“They are so desperate looking for a scandal it’s almost comical,” Carson said. “What they should be concentrated on is how are we going to solve the problems that we have. They can waste all of their time digging but they’re just not going to find anything.”

Breitbart took up this theme, calling CNN’s investigation “racially motivated.”

“The politics at play here are obvious,” John Nolte wrote. “Carson’s biography is a big part of his appeal. If CNN can destroy that and paint him as a liar while doing so, an existential threat to the Democrat Party — a black conservative — is eliminated.”

Still, in an era when embellished stories can lead to Brian Williams’s downfall — and when Mitt Romney’s prep school pranks became an issue in the 2012 campaign — stories from the past can matter. And CNN called Carson’s stories “vague and shifting.”

“What we set out to do was just simply to do what we do with any presidential candidate,” Reston said, “which was to vet this part of his life.”

This is not the first time Carson’s account of his past has been questioned. Just last month, the candidate responded to a Daily Beast report that characterized the tale as “full of holes.”

“For one thing, it happened 50 years ago — half a century ago,” Carson said. “For another thing, when people record what I’ve said, they record it in different ways. When you’ve got something from 50 years ago that’s told by many different people, it’s sort of like the party game where you whisper to people sitting in a circle. When it gets to the original person, it’s very different.”

At least one person thought the Carson stories worth looking into: sometime Republican frontrunner Donald Trump, Carson’s main competition in current polls for the presidential nomination. Fresh off of insulting Carson in a “Saturday Night Live” promo, the Donald took a shot at Carson on Thursday night.

“The Carson story is either a total fabrication or, if true, even worse — trying to hit mother over the head with a hammer or stabbing friend!” he tweeted.