* On Australia Day, 1966, the three Beaumont children, Jane, 9, Arnna, 7, and Grant, 4, left their parents' home in Adelaide and caught a bus to Glenelg Beach. They were amongst the many people seeking relief from the heat at the beach that day. They never returned.

* A major search, and an ongoing investigation over the past five decades, failed to find any trace of the children.

* In November 1966, Dutch clairvoyant Gerard Croiset claimed to have had a vision of where the children were buried. A search at the time and another 30 years later found nothing.

* There was a report the children were living in the Mud Islands, in Victoria's Port Phillip Bay, and in 1968 the entire crew of the British freighter Devon was questioned in New Zealand.

* Some years later, a Perth woman came forward to claim that for about nine months in 1966 she had lived next door to the Beaumont children in an isolated railway town near the SA-WA border.

* In 1997, a former investigator on the Beaumont case, Stan Swaine, said he believed a woman living in Canberra was actually Jane Beaumont. Police checked and rejected his story.

* About 40 years after the children's disappearance, convicted child murderer James O'Neill was suggested as a possible suspect but police ruled him out. Around the same time another child killer, Derek Percy, was interviewed in jail in Victoria and also discounted.

* In November 2013, police excavated the site of a North Plympton factory previously owned by a possible suspect in the case, Harry Phipps.

* Police also returned to the same site in February 2018 for another dig but found only animal bones.

* In September 2019, the mother of the three children, Nancy Beaumont, passed away in an Adelaide nursing home aged 92.

* The children's father Jim Beaumont is still alive.

Australian Associated Press