But since December 7, 2012, it has become a place of despair.

"I know my brother was murdered, that much I know," sister Torrie Martin told Fairfax Media.

"I believe whoever was at the property that night knows what happened."

Almost three years ago, 35-year-old Quinn Martin vanished after helping a mate in the back shed of the Colo Heights property in Sydney's north-west late at night.

His disappearance has left a string of broken relationships and dark suspicions in its wake as those close to the "good Aussie man with a beautiful heart" continue to search for answers.

Mr Martin and his former partner Jana Murphy went to the property – owned by Mr Martin's family friend Steve Borg – after dropping three of their children at Mr Martin's sister's home.

Ms Murphy and her two kids stayed in the farm house as Mr Martin and Mr Borg went to the back shed, which is partially visible from the house.

But after 10.30pm, Mr Borg returned on his own.

He later told police Mr Martin said he was going to see a mate and walked off towards an isolated, country road lined with thick bushland and no street lights.

"Police haven't been able to establish if he went there or who the friend was," Detective Inspector Paul McHugh said.

After getting "contradicting" answers about her partner's whereabouts, Ms Murphy searched for Mr Martin next morning. By nightfall she had reported her partner of 13 years missing to police.

The fact Mr Martin – known to most as "Dickie" – was due to be sentenced for an aggravated break and enter offence a week after his disappearance drove the police suspicion he may have run away.

Mr Martin had driven David Johnson to a house at East Kurrjong in April, 2012, before Johnson went inside and stole $30,000 worth of property.

Court documents state Mr Martin didn't go inside the house – owned by a friend's family – and drove off after waiting hours for Johnson to emerge.

He pleaded guilty to aggravated break enter and having a stolen bike in his possession.

With police now treating Mr Martin's disappearance as foul play, detectives say there has been no link "in any way, shape or form" made between this theory and Mr Martin's break and enter offence.

Last month, on the back of a recent media push, police discovered human bones over two days in the Parr State Conservation Area, behind the property Mr Martin was last seen.

His sister is now anxiously awaiting the results of forensic tests to confirm whether or not the bones belong to Mr Martin.

"They haven't confirmed it but I knew straight away it was Dickie," Ms Martin said.

"My main worry now is I want to see justice done, but I also want to put my brother to rest."

Ms Martin said her brother – also her best friend – was struggling before his disappearance following the loss of his mother and father.

"Because of the grief, he just wasn't looking out for himself and wasn't expecting anything," she said.

"He lost control. Dickie was mummy's boy and it broke his heart."

Mr Martin may have been grieving but he wouldn't have left his family behind, she said.

He grew up on NSW's north coast before moving to Sydney.

His family was close with Mr Borg, whose property Mr Martin's mother had camped on and Ms Martin had visited with her son.

It was during their time living in nearby South Windsor that Mr Martin also met Ms Murphy.

She held a media conference earlier this year, when police stated they had no idea what had happened to Mr Martin.

Asked what she made of the recent revelation that he had met with foul play, Ms Murphy told Fairfax Media this week: "I was a bit cranky to be honest ... one minute they (police) say he is alive and then this...I'm confused."

Ms Murphy is another relationship now with a man who used to work with Mr Martin at a concrete facility in Quakers Hill, friends say.

Earlier this year he posted on the NSW Police Force's Facebook page his views on Mr Martin.

"He is weak and ran like a scared girl," he posted in response to a media release about the case.

"Had a lot to run from."

Another comment from him read: "Best thing he ever done."

As Ms Martin, who has since moved from the Windsor area and the sadness it holds, clings to the memory of her brother, "a happy-go-lucky family man" with an insurmountable love for his children, she has a message for those with knowledge of the case.

"Just find it in your heart to tell the truth for his children's sake and to put him to rest," she said.

"Put yourself aside for once and think about his children and his family."