Australian police have begun excavating a factory site over the disappearance of three children more than 50 years ago.
The case of the Beaumont children is often described as Australia’s most enduring cold case mystery.
The children – Jane, nine, Arnna, seven, and Grant, four – vanished after visiting a beach in Adelaide in 1966.
Authorities said the site of the excavation was once owned by a person of interest in the case.
The new search followed a recently discovered “anomaly” in the soil, according to South Australia Police.
“We have our fingers crossed. We hope for the best, but we do want to temper expectations,” Detective Chief Inspector Greg Hutchins said on Friday.
The factory site, in the suburb of North Plympton, is about 5km (3 miles) from Glenelg Beach, where the children were last seen after going for a swim.
The property once belonged to a local businessman, Harry Phipps, who died in 2004. He remains a person of interest in the case.
A separate area of the site was excavated in 2013, but no evidence was discovered.
Police said their investigation would attempt not to cause unnecessary distress the children’s elderly parents, Grant and Nancy Beaumont.
“We all must remember the two Beaumont family parents who [have] suffered significantly over many, many years,” said Insp Hutchins.
Police said they hoped to complete their excavation on Friday, but it may require additional days.
The South Australian government has offered a A$1m (£560,000; $800,000) reward for information that helps solve the case.