Suspect Chris Dawson will still be pursued even if police find no body as they dig up the grounds of the Sydney home he shared with his wife Lyn who disappeared 36 years ago.
Forensic investigators started digging at the Bayview home on Wednesday and are examining "anomalies" in the garden.
Officers are digging by hand in a bid to finally rule out any suggestion Ms Dawson's body is buried at the home but police said a conviction is not dependent on finding her remains.
Homicide Squad Commander Detective Superintendent Scott Cook said they would still pursue charges against Mr Dawson even without a body.
"Absolutely, that's why I wrote to the director (of public prosecutions) in April," Det Supt Cook said.
The dig is expected to continue for at least five days.
"We will go until we hit rock," Det Supt Cook said.
"It's all about getting justice for Lyn."
The mother of two disappeared in January 1982 and, while her husband has long been a suspect, no charge has ever been laid.
Mr Dawson, who played professional rugby league for Newtown in the 1970s, has consistently denied any involvement in his wife's disappearance.
Four areas around the northern beaches home and in the backyard near a clothesline and pool - which was there before she was believed murdered - are being examined.
The areas being explored have been examined previously but not with the new technology now available.
"Previously when we conducted examinations here, there was a number of anomalies in the ground," Det Sup Cook said.
"They were inspected previously. We'll revisit them."
Holly Bouveng has lived in the previously peaceful street for three years, and as the sounds of power tools rang out on Wednesday she said she hoped police finally find the missing mother.
"It's the unknown at the moment, what did happen, is she still there and that's a little unnerving," she told AAP.
"It's so close to home."
"It breaks your heart, it's horrible, I just couldn't imagine."
Having been inside the home, Ms Bouveng said until recently she'd had no idea of its sinister past.
"It's just a lovely family home, there was nothing any different about it," she said.
Mr Dawson, a PE teacher at Cromer High at the time, was having an affair with a 16-year-old student when his 33-year-old wife disappeared.
The student, Joanne Curtis, moved in to the Dawson home within days of Ms Dawson's disappearance and later married Mr Dawson..
Ms Dawson spoke to her mother on the evening of January 8, while she was at home in Bayview with her husband.
She made lunch plans for the following day at Northbridge Baths but never showed up. Mr Dawson reported his wife missing on February 18.
The NSW Director of Public Prosecutions has twice declined to charge a known person with murder despite recommendations following coronial inquests in 2001 and 2003.