Canberra, Feb 2 (IANS): Investigators in the Australian city of Adelaide started excavating an industrial site on Friday for the remains of three children who went missing 52 years ago.

Nine-year-old Jane Beaumont, her sister seven-year-old Arnna and their four-year-old brother Grant, vanished after they went for a swim to the Glenelg beach on January 26, 1966.

Their disappearance is one of the infamous cold cases, and one that the police in Australia are desperate to solve to bring peace to the children's frail parents who are now in their 90s, CNN reported.

Friday's excavation is taking place at the Castalloy factory in North Plympton, which was once owned by businessman Harry Phipps, who died in 2004.

Phipps came to police attention in 2007 when a book was published that suggested he might be a credible suspect.

However, it was not taken seriously until two men came forward claiming to have been paid by Phipps to dig a trench at his factory site as teenagers.

Detective Superintendent Des Bray said police had previously searched the property in 2013, based on the information provided by the two men, but found nothing.

"It's clear that the two men did dig a hole. There's never been anything to prove that the Beaumont children are in the hole," said Bray, as he announced plans for the new excavation.

"Commonsense says if there's the slightest chance that the hole could be relevant we should search and that's what we're doing," he added.