A South Australian toy library has expressed sadness following the deaths of a mother and her two children, which police are treating as a murder-suicide.
The bodies of Helena Wright and her 23-month-old daughter were retrieved from waters off Cape Northumberland in SA's south-east on Monday.
The search for her three-month-old son was formally called off by South Australian Police on Wednesday afternoon, after receiving advice the child could not have survived.
Ms Wright was a volunteer committee member at the Mount Gambier Toy Library, which issued a statement on Thursday.
"Mt Gambier Toy Library is deeply saddened by the tragic loss of a member of our committee and her children. Our thoughts are with their family, friends and everyone affected by this devastating event," it said.
"Our volunteer committee and toy library community are grieving and supporting one another."
Police on Wednesday confirmed Ms Wright had attended a local police station on Sunday and officers had attended her home to conduct a welfare check on Monday morning following a call from a friend. Her car was found later that morning at Cape Northumberland.
The three deaths have shaken the Port MacDonnell community, which has rallied around locals who volunteered to help the police search.
The matter is now the subject of a coronial investigation.
