Arnna Kathleen Beaumont

Jane, Arnna and Grant Beaumont lived with their parents, Grant "Jim" Beaumont, a former serviceman and taxi driver, and Nancy Beaumont (née Ellis); the couple had married in December 1955.

The family resided at 109 Harding Street, Somerton Park, South Australia, a suburb of Adelaide.

They lived not far from Glenelg Beach, a popular spot that the children and many others at the height of the surf music era often visited.

Jane Nartare Beaumont (born 10 September 1956), Arnna Kathleen Beaumont (born 11 November 1958) and Grant Ellis Beaumont (born 12 July 1961), collectively referred to as the Beaumont children, were three Australian siblings who disappeared from Glenelg Beach near Adelaide, South Australia, on 26 January 1966 (Australia Day) in a suspected abduction and murder.

Police investigations revealed that, on the day of their disappearance, several witnesses had seen the three children on and near Glenelg Beach in the company of a tall man with fairish to light-brown hair and a thin face with a sun-tanned complexion and medium build, aged in his mid-thirties.

Confirmed sightings of the children occurred at the Colley Reserve and at Wenzel's cake shop on Moseley Street, Glenelg.

Despite numerous searches, neither the children nor their suspected companion were located.

The case received worldwide attention and is credited with causing a change in Australian lifestyles, since parents began to believe that their children could no longer be presumed to be safe when unsupervised in public.

On 25 January 1966, in the midst of a summer heatwave, Jim dropped the children off at Glenelg Beach before heading off on a three-day sales trip to Snowtown.

On the morning of 26 January (Australia Day), the Beaumont children asked their mother to visit Glenelg Beach again.

As it was too hot to walk, they took a five-minute, three-kilometre bus journey from their home to the beach.

The children caught the bus at 8:45 am and were expected to return home on the 12:00 noon bus.

Nancy became worried, however, when the siblings did not return on either the 12:00 or 2:00 pm buses, and when Jim returned home early from his trip around 3:00 pm, he immediately drove to the crowded beach.

Unable to locate the children, he returned and together both parents searched the streets and visited friends' houses.

Around 5:30 pm, they went to Glenelg police station to report the disappearance.

Police quickly organised a search of Glenelg Beach and adjacent areas, based on the assumption that the Beaumont children were nearby and had simply lost track of time.

The search then expanded to the sand-hills, ocean and nearby buildings, with the airport, rail lines and interstate roads being monitored as well, based on a fear of accident or kidnap.

Within twenty-four hours, the entire nation was aware of the case.

Within three days, on 29 January, the Adelaide Sunday Mail led with a headline of "Sex crime now feared", highlighting the rapidly evolving fear that the children had been abducted and murdered by a sex offender.

Despite this, the initial official reward was only A£250.

The Patawalonga Boat Haven was drained on 29 January after a woman told police that she had spoken with three children, who were similar in description to the Beaumont children, near the haven at 7:00 pm on the day of the disappearance.

Police cadets and members of the emergency operations group searched the area, but nothing was found.

Police investigating the case found several witnesses who had seen the Beaumont children in Colley Reserve, near Glenelg Beach, in the company of a tall man with fair to light brown hair and a thin face, and in his mid-thirties.

The man had a sun-tanned complexion and a thin-to-athletic build, and was wearing swim trunks.

The children were playing with him, and appeared to be relaxed and enjoying themselves.

The man also approached one of the witnesses, asking if anyone had been near the children's belongings as their money was "missing".

The man then went off to change while the children waited for him.

The group were then seen walking away together from the beach sometime later, which the police estimated to be around 12:15 pm.

About two-and-a-half hours later another witness, Miss Daphne Gregory, sighted the children with the man, who she observed carrying an airline bag similar to one owned by Jane.

The Beaumont parents described their children, particularly the eldest Jane, as shy.

For them to be playing so confidently with a stranger seemed out of character.

Investigators theorised that the children had perhaps met the man during a previous visit or visits and had grown to trust him.

A chance remark at home, which seemed insignificant at the time, supports this theory: Arnna had told her mother that Jane had "got a boyfriend down the beach".

Nancy thought she meant a playmate and took no further notice until after the disappearance.

A shopkeeper at nearby Wenzel's Bakery, on Moseley Street, reported that Jane had bought pasties and a meat pie with a £1 note.

Police viewed this as further evidence that the Beaumont children had been with another person, for two reasons: the shopkeeper knew the children well from previous visits and reported that they had never purchased a meat pie before, and the children's mother had given them only six shillings and six pence, enough for their bus fare and lunch, and not £1.

Police believed the money had been given to them by somebody else.

In recent years, police and media speculation has linked the disappearances to the Adelaide Oval abductions of 1973.

Interest in the case has continued more than half a century on.

, a $1 million reward has been offered for information related to the cold case by the South Australian government.