Attention is focused on a small section of ground at the North Plympton site where recent scientific tests revealed the possible presence of a large hole dug there around the same time the three children went missing in 1966.
Detective Chief Inspector Greg Hutchins told reporters there were innocent explanations for the anomaly those tests uncovered, but it could also be a major breakthrough in Australia’s most enduring cold case.
“The anomaly (…begins) about another 80 centimetres from where we are now,” he said.
“Once we hit that point it’s approximately a metre below where it’s most prevalent … I think we will get to that level this afternoon.
“As we get closer to the anomaly we will need to be guided by the experts (and) the forensic anthropologist, who is on site.”
The dig is expected to continue for at least several hours.
The Beaumont children never returned after leaving their parents’ Glenelg home for an afternoon at the beach on Australia Day, 1966.
Their disappearance sparked a wide-scale search operation, but nine-year-old Jane, seven-year-old Arnna and four-year-old Grant were never found.
In 2013, new information focused the investigation on the factory, after two brothers told police they spent the 1966 Australia Day weekend digging a large hole there at the request of owner Harry Phipps.
Phipps died in 2004, but his son, who accused his father of years of sexual abuse, believed he had a part in the crime.
He also bore a resemblance to an identikit picture prepared at the time, and lived close to Glenelg Beach.
An initial excavation at the North Plympton site proved fruitless, but police now believe they may have been digging in the wrong spot.
Hutchins said SA police had been in regular contact with the parents of the children, Jim and Nancy Beaumont, and had informed them of today’s activity.
“Clearly the parents of the three Beaumont children have suffered significantly over the last 52 years,” he said.
A range of experts are present at the site including a forensic anthropologist, a criminologist, crime scene examiners and officers from the major crime division.
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