Marianne Schmidt and Christine Sharrock were both 15 years old, close friends and next-door neighbours in the Sydney suburb of West Ryde. Schmidt had come to Australia from West Germany with her family in 1958; Sharrock lived with her grandparents. On Monday 11 January 1965, the two girls travelled by train to Cronulla, in southern Sydney, accompanied by four of Schmidt's younger siblings. They reached the beach around midday, but strong winds had left it largely deserted.
In the early afternoon the pair walked north into the sandhills behind Wanda Beach, leaving the younger children waiting near the family's belongings. They did not return. The children waited into the evening before travelling home, and the girls were reported missing that night. The following morning, 12 January, a man walking with his young nephews through the dunes discovered their partially buried bodies a short distance north of the Wanda Surf Club.
Both girls had been fatally attacked. Evidence at the scene, including a long drag mark in the sand, indicated that one had tried to flee before being caught. Both had suffered stab wounds and severe injuries, and investigators concluded that attempts had been made to sexually assault them. The weapons used were never recovered despite an extensive search of the surrounding sand.
The killings prompted one of the largest police investigations in Australian history. Within about a year, detectives had interviewed thousands of people, and over the following decades the number questioned grew far larger. A substantial reward was offered for information. Numerous individuals were considered over the years, but none was ever charged, and the identity of the person responsible was never established.
The case was formally reopened in 2000. In 2012, the New South Wales Police cold case unit reported that a weak male DNA profile had been recovered from clothing worn by one of the girls, though the sample was too limited to identify anyone with the technology of the time. In 2014, police disclosed that a forensic sample taken from the other victim decades earlier could no longer be located.
More than sixty years after the crime, the matter remains open with the Homicide Squad's Unsolved Homicide Unit, which continues to monitor it for new information. No one has ever been charged. The Wanda Beach murders are frequently described as New South Wales' oldest unsolved homicide case, and the loss of two teenage girls on a summer afternoon has remained a source of grief for their families and communities. Police continue to appeal for any information that might help resolve what happened to Marianne Schmidt and Christine Sharrock.