South Australian police are investigating the deaths of Helena Wright, 36, and her 23-month-old daughter as a murder-suicide. Their bodies were discovered in the ocean off the coast west of Port Macdonnell on Monday.
Emergency services were called to the area after an abandoned vehicle was found with its engine running at 11.15am. Ms Wright, originally from Estonia, had been living in Compton, near Mount Gambier.
A three-month-old boy, Ms Wright's son, remains missing. Police have stated that hopes of finding the infant alive have faded, describing the ongoing search as a "retrieval effort". Supt Trent Cox said on Wednesday that after three days, the chances of finding the baby alive are "zero".
Police have spoken to the woman's husband, the father of the children, and indicated there is no information to suggest anyone other than the mother and her two children were involved. The incident has been referred to the coroner to examine the cause and circumstances of the deaths.