Sirhan Sirhan was denied parole Wednesday for fatally shooting Robert F. Kennedy after a confidante of the slain senator who was shot in the head forgave him and repeatedly apologized for not doing more to win his release.

Paul Schrade's voice cracked with emotion during an hour of testimony on his efforts to untangle mysteries about the events of June 5, 1968. The 91-year-old former labor leader said he believed Sirhan shot him but that a second unidentified shooter felled Kennedy.

"I should have been here long ago and that's why I feel guilty for not being here to help you and to help me," Schrade said.

The men faced each other for the first time since Schrade testified at Sirhan's 1969 trial. Schrade apologized for not going to any of Sirhan's 14 previous parole hearings.

As Sirhan left, Schrade shouted, "Sirhan, I'm so sorry this is happening to you. It's my fault."

Sirhan, who had nodded politely when the victim addressed him, tried to shake hands with Schrade but a guard blocked him.

Commissioners concluded after more than three hours of intense testimony at the Richard J. Donovan Correctional Center that Sirhan did not show adequate remorse or understand the enormity of his crime.

Sirhan, who is serving a life sentence that was commuted from death when the California Supreme Court briefly outlawed capital punishment in 1972, will next be eligible for parole in five years.

"This crime impacted the nation, and I daresay it impacted the world," commissioner Brian Roberts said. "It was a political assassination of a viable Democratic presidential candidate."

Sirhan, 71, stuck to his account that he didn't remember the shooting at the Ambassador Hotel in Los Angeles moments after Kennedy delivered a victory speech in the pivotal California primary.

Sirhan recalled events before the shooting in some detail — going to a shooting range that day, visiting the hotel in search of a party and returning after realizing he drank too many Tom Collins' to drive. He drank coffee in a hotel pantry with a woman to whom he was attracted.

The next thing he said he remembered was being choked and unable to breathe.

'It's all vague now': Sirhan

"It's all vague now," he said. "I'm sure you all have it in your records, I can't deny it or confirm it. I just wish this whole thing had never taken place."

Sirhan, a native of Jerusalem, listened intently during most of the hearing, turning testy when commissioners pressed him on his memory and any feelings of remorse. He said he felt remorse for any crime victim but added that he couldn't take responsibility for the shooting.

"If you want a confession, I can't make it now," Sirhan said. "Legally speaking, I'm not guilty of anything. ... It's not that I'm making light of it. I'm responsible for being there."

Sirhan Sirhan

This file photo from June 1968 shows Sirhan Bishara Sirhan, right, accused assassin of Sen. Robert F. Kennedy with his then attorney Russell E. Parsons in Los Angeles. (The Associated Press)

Schrade, who was alongside Kennedy and four others who were injured and served as western regional director of the United Auto Workers Union at the time, provided much of the drama. He angrily ignored the commissioner's admonishment to avoid directly addressing Sirhan and chastised the prosecution for a "venomous" statement advocating that Sirhan stay in prison.

Schrade, who long advocated the second-gunman theory, recalled how he became depressed and upset after the shooting and vividly described his extensive efforts to find answers. He stopped occasionally to apologize for being nervous and emotional.

The commissioner asked Schrade to wrap up after about an hour, saying, "Quite frankly, you're losing us."

"I think you've been lost for a long time," Schrade shot back.

At one point, the commissioner asked if anyone wanted a break.

"No, I want to get this over," Schrade answered from the audience. "I find it very abusive."

David Dahle, a retired prosecutor appearing for the Los Angeles County district attorney's office, said Sirhan was guilty of "an attack on the American political system and the American political process."

"The prisoner has still not come to grips with what he has done," he said.

In one of many emotional outbursts during his 1969 trial, Sirhan blurted out that he had committed the crime with 20 years of malice aforethought.

That and his declaration when arrested, "I did it for my country," were his only relevant comments before he said he didn't remember shooting Kennedy.

Sirhan said incriminating statements he made at trial were the result of an ineffective defence attorney who pressured him into thinking he was guilty.

"I feel if I had a proper defence at the time then the results would have been quite different," he said.

Sirhan said he was initially reluctant to attend the hearing — feeling he was mistreated at his last appearance in 2011 — but his attorneys successfully urged him to reconsider.

Sirhan told the panel that if released, he hoped he would be deported to Jordan or would live with his brother in Pasadena, California.

His hope, he said, was "just to live out my life peacefully, in harmony with my fellow man."

"This is such a traumatic experience, it's a horrendous experience that for me to keep dwelling on it is harmful to me," Sirhan said.