Six children of Robert F Kennedy have condemned the decision to grant parole to Sirhan Sirhan, the man who shot and killed the New York senator as he ran for the Democratic presidential nomination in 1968.

“He took our father from our family and he took him from America,” the six said in a statement late on Friday. “We are in disbelief that this man would be recommended for release.”

The statement was signed by Joseph P Kennedy II, Courtney Kennedy, Kerry Kennedy, Christopher G Kennedy, Maxwell T Kennedy and Rory Kennedy.

Two Kennedy children supported the decision.

Douglas Kennedy, a toddler when his father was killed, said he was “overwhelmed just by being able to view Mr Sirhan face to face. I’ve lived my life both in fear of him and his name in one way or another. And I am grateful today to see him as a human being worthy of compassion and love.”

Robert F Kennedy was US attorney general under his older brother, John F Kennedy, when the president was assassinated in Dallas in 1963. Five years later the younger Kennedy was a senator from New York when he was killed at the Ambassador hotel in Los Angeles, moments after delivering a victory speech in the California primary. Five others were wounded.

Sirhan, now 77, insists he does not remember the shooting and had been drinking beforehand but was convicted of first-degree murder. He was sentenced to death, commuted to life when the California supreme court briefly outlawed capital punishment.

The hearing on Friday was his 16th attempt to gain parole. Because of laws passed in 2018, the board was required to take into account the fact that Sirhan suffered childhood trauma from the conflict in the Middle East, committed the offense at a young age and is now elderly.

Appearing by video from a San Diego county prison, Sirhan said: “Senator Kennedy was the hope of the world … and I harmed all of them and it pains me to experience that, the knowledge for such a horrible deed, if I did in fact do that.”

The board found Sirhan no longer poses a threat to society, noting his enrollment in programmes including anger management classes, Tai Chi and Alcoholics Anonymous, even during the coronavirus pandemic.

“We think that you have grown,” commissioner Robert Barton said.

The ruling will be reviewed over 120 days then sent to the governor, who will have 30 days to decide whether to grant, reverse or modify it. If Sirhan is freed, he must live in a transitional home for six months, enroll in an alcohol abuse program and get therapy.

The six Kennedy children who oppose release said they were “devastated” and appealed to the governor, Gavin Newsom, “to reverse this initial recommendation” which had “inflicted enormous initial pain”.

“Sirhan Sirhan committed a crime against our nation and its people,” they said, adding: “We hope that those who also hold the memory of our father in their hearts will stand with us.”

The Los Angeles police department, relatives of some victims and members of the public submitted letters opposing release.

Paul Schrade, a union leader and aide to Robert Kennedy who was among five wounded in the 1968 shooting, spoke in favour of release.

Robert F Kennedy Jr, who has spoken for release in the past, wrote in favor of parole. He said he was moved by Sirhan, “who wept, clinching my hands, and asked for forgiveness” when they met in prison.

“While nobody can speak definitively on behalf of my father, I firmly believe that based on his own consuming commitment to fairness and justice, that he would strongly encourage this board to release Mr Sirhan because of Sirhan’s impressive record of rehabilitation.”

Some of Kennedy’s children and others have called for a reinvestigation, believing there was a second gunman.