On the eve of his 90th birthday in September 2015 Kenneth Handford was tied up and stabbed at his isolated home on the Barkstead Road by two men.

Adam Lucas Williamson, 40, faced the Victorian Supreme Court on Tuesday when he pleaded guilty to murdering the elderly man and robbing him.

"It (the stabbing) takes place in the course of what amounts to an armed robbery," prosecutor Justin Lewis told the court.

Williamson admitted stealing cash, a gold chain, a phone and nearly a dozen war medals from Mr Handford.

Tuesday's hearing was the second time Williamson has pleaded guilty over the killing. He previously admitted the murder but changed his mind, rescinding his plea in December 2016.

The judge made it clear to the killer that he cannot change his mind again.

"He's bound by that plea," Justice Jane Dixon said.

Defence lawyer Scott Johns provided some reassurance.

"It's what Mr Williamson wants to do."

Williamson admitted he knew Cooper had a double-bladed knife when they set out on the robbery.

Neighbours found Mr Handford's body bound, beaten and bloodied on September 15, 2015 which would have been his 90th birthday.

Williamson is due to face a pre-sentence hearing on October 10.

In April the 29-year-old man Jonathon Cooper who stabbed Mr Handford was jailed for 16 years, 13 of which he will need to serve before he is eligible for parole.

His discounted sentence came as a shock to some of Mr Handford’s family members whose call advocating for a more severe sentence resulted in a petition of 30,000 signatures being presented to the Victorian attorney general.

Following the 2015 murder, Mr Handford was found lying face up, with his hands bound by his dressing gown cord and legs tied to his bed on the morning of September 15, his 90th birthday.

He had been stabbed 13 times in the back, with a sock which is believed to have been used as a gag lying beside him.

At the earlier trial the court heard Cooper  had hit Mr Handford, who woke up during the aggravated burglary, in the head with his torch.

Cooper used the same torch to hit Mr Handford’s hand as he reached for a phone.

The court heard earleir this year after the stabbing attack, the accused men left the house with Mr Handford’s WWII medals, jewellery and $3900 in cash.

Mr Handford's pace maker showed he spent four hours and 38 minutes lying on the floor until he succumbed to his injuries.

The court also heard Cooper had  showed a friend his bloody knife and clothes following the tragic murder.