20 years jail for bashing 'defenseless' intellectually disabled, homeless man to death

A callous killer who laughed after mugging and beating an intellectually disabled, homeless man to death in an unprovoked attack has been jailed for 20 years.

Robert John Marshall, 22, of Keysborough, pleaded guilty to the murder of Christian Williams, whom he attacked “for no reason” in Dandenong Park on November 18, 2014, beating and stomping on him until he was dead.

Mr Williams was found dead and shirtless, with significant upper body injuries, the following day by an off-duty Protective Services Officer walking his dog.

The man who bashed Intellectually disabled homeless man Christian Williams (pictured) to death has been sentenced to 20 years behind bars. Picture: Supplied

Victorian Supreme Court judge Justice Karin Emerton branded the attack on the father of one as "sickening", on Tuesday.

The court heard that the 43-year-old “overgrown kid” had the mentality of a 12-year-old after a brain injury suffered as a child when he was hit by a car.

Justice Emerton ordered Marshall to serve a minimum of 16 years, stating he showed a complete disregard for Mr Williams' humanity.

"He died pointlessly and tragically in terrifying circumstances," Justice Emerton said Mr Williams.

The day of the murder, the victim was listening to music and preparing to sleep at the sound stage in Dandenong Park.

Marshall had been drinking with friends in the area before he approached Mr Williams and demanded his wallet.

Marshall then hit him in the head without provocation.

The court described the unprovoked attack as 'sickening' as Robert John Marshall (pictured) continued to beat the victim even after he lost consciousness. Picture: 7 News

A friend tried to restrain Marshall who punched Mr Williams four of five more times.

As Marshall continued his assault, Mr Williams did not fight back, but instead began crying and asking: "What did I do?” the court heard.

Even after the victim lost consciousness, Marshall continued to punch him, Justice Emerton said.

A friend said to Marshall: "Look you've killed him".

“You laughed and said: ‘I don’t care,’” the judge recounted.

Mr Williams was found dead and shirtless, with significant upper body injuries, by an off-duty Protective Services Officer walking his dog. Picture: 7 News

“You then stomped on Mr Williams’ face, stomach and chest with such force that the imprints of your shoes were left on his body.

“The attack on Mr Williams was unprovoked. It was brutal and protracted, and Mr Williams was vulnerable and defenseless.

“Your conduct was particularly vicious and contemptuous. You showed a complete disregard for Mr Willams’ humanity,” she said.

"Your conduct can only be described as sickening," Justice Emerton said on Tuesday.

The November 2014 attack was believed to have happened at this ampithearte at Dandenong Park, where Mr Williams was known to sleep. Picture: 7 News

Mr Williams' family is happy with the sentence but says Marshall shouldn't have been out on the streets given his criminal history.

"There were so many red flags," the victim's sister, Mandy Stevens, said.

"What he did was disgusting and I'm surprised he was out on the street.

"He'll still be younger than my brother when he gets out."