The macho 26-year-old star fell to the ground after being wounded by the point-blank blast of a prop pistol, bringing the program's production to a stop.
Sources on the set have described a series of ironic events that led up to the accident.
"Only hours before the gun went off, he was off-camera with his co-star Jennifer O'Neill," said one insider.
"Jennifer was telling him about her own accident with a gun in New York two years ago. She had accidentally shot herself in the stomach."
The insider said Hexum was interested in O'Neill's story, but the conversation turned back to acting.
"Hexum was saying how he didn't want to be known as a pretty face or a good body.
"He said tht he wanted to become an actor's actor. he said he wanted to play serious roles," the insider continued.
"The movie Deerhunter, which starred Rober DeNiro, was the kind of production he wanted to get involved in.
"They started talking about those tense scenes where the prisoners are forced to play Russian roulette.
"It really is an incredible coincidence that later that afternoon, Hexum himself would put the prop gun to his head and pull the trigger.
"But at the same time, it's likely Jon didn't know the blanks could cause serious injury at close range.
"It was a tragic mistake."
O'Neill, who was charged with -- but cleared of -- illegal possession of a revolver after her accident in her Bedford Hills, NY home on Oct. 22, 1982, has refused to talk about Hexum's accident.
Hexum, whose family flew to his bedside at the Beverly Hills Medical Center after the tragedy, was on the verge of his first hit TV series.
The blast from the blank cartridge shattered the skull bone at Hexum's right temple. Though the bone did not pentrate the brain, the brain was badly bruised by the impact.
Officer Gary Fullerton of the West Los Angeles police said Hexum shot himself using blanks and dummy bullets.
"Dummy bullets don't go off at all," Fulletrton said. "The blanks detonate but contain only wadding instead of lead. They are dangerous at close range."
Witnesses told police that Hexum loaded the five-chamber .44 Magnum-brand revolver with three dummies and two of the potentially dangerous blanks.
He was seen to spin the chamber, put the gun to his head and say: "Let's see if it goes off this time."
Fullerton said he doubted that Hexum knew the danger of the blanks exploding so close to his head: "He had too much of a future, too much to live for. It was just a game."
Hexum, who ironically plays the part of a weapons expert on the series, had not been himself for the last two weeks on the set, according to the insider.
"A number of people on the series noticed tht John wasn't his usual open, friendly self in the week leading up to the accident," said the source.
Another insider on the set added: "In the last two weeks, something peculiar seemed to have happened to him. He was acting as though in a daze.
"When you talked to him, he didn't seem to be listening, to comprehend what you said. His eyes were kind of blank and he would stare off into the distance.
"I can't begin to speculate what the problem was. All I can say is that it was bizarre.
"We are all just totally shocked. The guy had just gotten the biggest break of his life.
"He was doing great on the show. Everybody liked him. He had his whole life ahead of him. All I can say is he suddenly started acting strangely, and then this.
"I hope someone is looking into this, retracing his steps and finding out just what happened to him. It didn't just start that Friday. It goes back a couple of weeks."
Jon-Erik Hexum, star of the new TV series "Cover Up," was playing a bizarre game of Russian roulette when he shot himself in the head in front of the show's cast and crew, reveal eyewitnesses.
The muscular, handsome Hexum, 26, was using a pistol loaded with blanks -- and apparently didn't realize that the gun, a powerful .44-caliber magnum, can kill at close range even when blanks are used.
Ironically, his leading lady on "Cover Up," Jennifer O'Neill, also shot herself two years ago.
Recalling the shooting of Hexum on October 12, a crew member who was present said:
"Jon had just finished shooting a scene and was unloading the gun as he was sprawled out on the bed of a hotel room set. He put the cartridges on a bedside table.
"Jon lay there smiling -- then he put two or three of the blanks back into the revolver and swung the gun back to his head.
"A worried camera assistant shouted, 'What are you doing?' Jon laughed as though he were having the best time in the world and called back, 'Playing Russian roulette!'
"Then, with the gun at his right temple, Jon smiled and pulled the trigger. There was a loud bang and a bright flash, then black smoke.
"Jon screamed in agony, then looked kind of amazed as he slumped back onto the bed with blood streaming from a severe head wound. It was horrible!"
Said another eyewitness: "One of the assistants rushed over to Jon with a towel and wrapped it around his head, trying to stop the blood."
A top police firearms expert told The ENQUIRER:
"A .44 magnum is one of the most powerful handguns around -- even with a blank load. The paper wadding could pierce your skin even from several feet away. And if the gun was held at a close distance there's no doubt it would cause severe damage and could possibly kill. At the least it would fracture a skull."
After the shooting, someone rushed off to call an ambulance, the second eyewitness said. But before it arrived several of the crew carried Jon out to one of the studio's station wagons and drove him to the hospital.
At Beverly Hills Medical Center, doctors and nurses worked furiously to keep him alive. At 7:30 p.m., following a CAT scan and some other tests, he was wheeled into surgery.
While Hexum's life hung by a thread, close friends gathered in the hospital's waiting room and kept vigil for hours. ENQUIRER reporter Richard Taylor, who also was there, reported:
"Hexum's friends spoke in hushed tones as they tried to comfort each other. Some paced the floor.
"Hexum's girlfriend, Elizabeth Daily, sat on a hospital bench, her eyes red from crying.
"She was wringing her hands over and over as she said, 'Oh, God please let him be O.K. Let him live! Everything was going so wonderful for him -- and now this!'
"Around 9 p.m., Hexum's mother Gretha arrived from Los Angeles International Airport after flying in from Las Vegas.
"She ran into the waiting room and was greeted by friends, who tried to comfort her."
Almost exactly two years earlier, on Oct. 22, 1982, Jon's costar Jennifer O'Neill also shot herself -- firing a .38-caliber bullet into her stomach at her mansion in Bedford Hills, NY. Jennifer told police the gun went off accidentally.
Hexum landed his role on "Cover Up" after he co-starred opposite Joan Collins of "Dynasty" in the TV-movie "The Making of a Male Model," last year. When Collins learned of the tragedy, she was stunned, according to a close friend.
Joan told the friend: "I can't believe something this terible could happen to Jon. He loved life more than almost anyone."
--Robert G. Smith
Back to the JEH Remembrance Page