Police say they are "hopeful" of finding the body of Roxlyn Bowie, 36 years after her disappearance and suspected murder, after new information led them to investigate two sites in northern NSW.
The search comes three weeks after a $1 million reward was announced for information relating to the suspected murder of the mother-of-two.
Robbery and serious crime squad commander, Superintendent Daniel Doherty said officers began forensically searching and digging up a dam in Walgett on Monday, and on Tuesday they began their examination of a nearby industrial site.
Both sites are not far from where Roxlyn was last seen, leaving her family's home about 6pm on Saturday June 5, 1982.
The superintendent said investigators were "hopeful" the sites held the key to what happened to Ms Bowie, who was 31 when she disappeared.
“Ultimately, what we’d like to find is evidence that may lead us to the location of Roxlyn’s body," he said.
The search is expected to take at least three weeks, and Superintendent Doherty said police "will not give up on this investigation".
"It’s been 36 years since Roxlyn disappeared, and that’s a long time for [Ms Bowie's daughter] Brenda and her family to not know the truth of what happened," he said.
"So whilst we’ll never take away the burden of grief, we can lessen the burden of grief."
Investigators from Strike Force Maluka have targeted the dam and industrial site after receiving information from the public.
Superintendent Doherty said the concrete slab at the industrial site was laid around the time of Ms Bowie's disappearance, and they would be using specialist technology to examine the slab.
"I can’t stress enough how crucial information is that we do receive from members of the public," he said.
The renewed investigation follows a September 2014 coronial inquest into the disappearance of the "devoted mother" which found the 31-year-old had died on or around the date of her disappearance – but while it was "highly likely" she had met with foul play, the cause of death was unable to be determined.
Earlier this month, Superintendent Doherty said Ms Bowie was described as "a quiet and shy woman, and a beloved daughter and mother".
"From all accounts, Mrs Bowie was utterly devoted to her two young children, which makes her disappearance very puzzling to those who knew her well."
During the inquest, counsel assisting the coroner Sergeant Paul Bush said Mrs Bowie had planned a party for her son's second birthday before she disappeared.
Her daughter Brenda, who was six at the time her mother disappeared, told the inquest her mother was "most affectionate" and recalled baking cakes with her.
Roxlyn's husband John Bowie also spoke at the inquest, and was open about his own behaviour including drinking and extramarital affairs. He also admitted to forging his wife's signature on a land transfer document in 1984.
Coroner Mary Jerram said she "put very little weight" on some of his evidence, but letters to her husband and parents announcing her intention to leave remained "a stumbling block".