The Beaumont children were three siblings, Jane Nartare Beaumont (born 10 September 1956), Arnna Kathleen Beaumont (born 11 November 1958), and Grant Ellis Beaumont (born 12 July 1961), who disappeared from Glenelg Beach near Adelaide, South Australia, on Australia Day, 26 January 1966. At the time of their disappearance they were aged 9, 7 and 4 respectively.
Their case resulted in one of the largest police investigations in Australian criminal history and remains one of Australia's most infamous cold cases, even after fifty years. The huge attention given to this case, its significance in Australian criminal history, and the fact that the mystery of their disappearance has never been explained, has led to the story being regularly revisited by the press. It is also viewed by many social commentators as a significant event in the evolution of Australian society, with a large number of people changing the way they supervised their children daily.
The children lived with their parents Jim and Nancy Beaumont in a house at 109 Harding Street, Somerton Park, a suburb of Adelaide. Not far from their home was Glenelg, a popular beachside resort, that the children often visited. On 26 January 1966, the children took a five-minute bus journey from their home to the beach; they had taken a similar trip to the beach the day before. Jane, the eldest child, was considered responsible enough to care for the two younger siblings, and their parents were not concerned. They left home at 10 am and were expected to return home by 2 pm. Their parents became worried when they had not returned and called the police at 7:30 pm.
Police investigating the case found several witnesses who had seen the children near the beach in the company of a tall blond and thin-faced man with a sun-tanned complexion of thin to athletic build in his mid-30s. The children were playing with him and appeared relaxed and to be enjoying themselves. The man and the children were seen walking together as a group away from the beach some time later, which the police estimated to be around 12:15 pm. A shopkeeper reported Jane Beaumont had bought pasties and a meat pie with a A£1 note.