Almost 50 years later, Jansen was finally sentenced for manslaughter.

At the age of 26, Jansen met Keen while drinking in Brisbane and agreed to go to his hotel room for a meal in August 1976.

Jansen – now 72 – did not want a sexual encounter but suspected Keen was gay or bisexual, the Brisbane Supreme Court heard.

Keen told Jansen that he could “pay for the meal with his body” and that he also wanted to take his picture.

When Keen then approached with a camera, Jansen feared it was a sexual advance.

In what was described as a “dramatic, complete over-reaction”, Jansen grabbed the camera and struck Mr Keen with it, hoping to knock him out.

In the end Jansen hit him up to a dozen times with the heavy camera, leaving Keen semi-conscious and moaning in his hotel room.

“In terms of perceived provocation … your over-reaction occurred in a different era when homosexuality was unlawful and perceived differently by some parts of society,” Justice Declan Kelly said.

“However … it was absolutely no excuse for the way you reacted.”

The camera has never been found after Jansen took it as he left, later burying it near his home.

Hotel staff discovered Keen’s body the next morning lying in a substantial pool of blood on the bed.

He had 11 head lacerations and a fractured skull. The fracture may have been suffered due to a fall, the court heard.

Keen was alive for some considerable time without assistance or care after the attack, dying up to eight hours following the assault.

DNA found on a tissue in the hotel room was identified as Jansen’s in January 2019 and led to his arrest six months later after 43 years on the run.

When arrested, an upset Jansen told officers Keen’s family “wouldn’t want to know what happened”.

However Keen’s family said the “heinous, violent and unjustifiable attack” had been a source of suffering but Jansen’s sentencing had brought some closure.

They described Keen as a “hardworking, resilient and respectable person” who was highly regarded by his family and community.

“Too often, in violent cases such as this, the perpetrator’s actions or motive are focused on, resulting in misperceptions or speculation which only disempowers victims,” a Keen family statement said.

“We hope that the outcome of this cold case investigation provides a glimpse of hope to those families who are yet to have answers or justice.

“…And it is our hope that this case inspires others to come forward with any information that may help police investigators.”

Justice Kelly said Keen’s death was “deeply felt” by his family who had lost a beloved son, brother and uncle.

“Mr Keen’s mother died never knowing why or the circumstances in which her son was killed,” he said.

“That is a particularly sad and disturbing feature of this case.

“It was always in your power to come forward and explain what had occurred but you did not.”

Some of Keen’s family attended court to hear Jansen being sentenced to nine years’ jail after pleading guilty to manslaughter.

He is immediately eligible for parole with his 1205 days in custody declared as time served.