A mother has allegedly tried to drown her two sons in the Murray River, leaving one boy in hospital and police searching the water for the second.
The woman, from Deniliquin, is in hospital undergoing assessment and is expected to be extradited from Victoria to NSW to face charges after handing herself in to police at Echuca on Thursday night.
NSW Police hope she will appear at Deniliquin Local Court on Friday.
Fairfax Media understands police will allege she told her family yesterday that they would never see her sons, aged five and nine, again.
She then allegedly travelled more than 70 kilometres from Deniliquin to a part of the Murray River near Moama, on the NSW-Victoria border.
As she was allegedly drowning her sons, a pit bull dog belonging to a nearby resident was somehow alerted to the commotion and became involved.
It is understood the nine-year-old boy sustained several dog bites but it allowed him to escape the water.
The Royal Children's Hospital in Melbourne said he is in a critical condition.
The five-year-old is still missing. A search by NSW and Victoria police, SES and Maritime Rescue began on Thursday evening but was called off at 11pm, before being restarted at 8am on Friday.
Thirty searchers are combing the river, with Victorian Police divers and spotter planes are also taking part in the search.
The Riverine Herald has reported police have already recovered a small T-shirt from the river.
In an emotional police press conference on Friday afternoon, Deniliquin Local Area Commander Superintendent Paul Condon revealed the mother was also bitten by the dog.
She was then last seen with her five-year-old son in the river, he said.
"About 10pm, a 27-year-old female has presented to Echuca police station, where she was conveyed to Echuca hospital for severe dog bites.
"The 27-year-old female was interviewed by Deniliquin detectives this afternoon and they are now preparing documents for her extradition and charge of attempted murder.
"So far the search has involved searching the riverbank where [the boy] was last seen as well as using Victoria Police divers to search the river."
Superintendent Condon said there had been "a couple of incidents" with the family since the mother was released from jail.
"We've had a brief conversation with the nine-year-old last night and we haven't had another. He requires some surgery for the dog bites and of course he's distressed; he's a nine-year-old boy."
He said it was a "terrible story" and a "tragic story" for the border town community, but would also have a wider impact.
"I think it will rock the community of Australia," he said.
The situation unfolded at 7pm on Thursday, when police were called to Perricoota Road, Moama, where the nine-year-old was found with serious dog bite injuries.
He was rushed to hospital in Echuca before being transferred to Melbourne for further treatment.
Shortly after that, police received information the boy's five-year-old brother was missing in the Murray River.
Some time after 8pm on Thursday, the mother wandered onto a property near Moama where she had a conversation with a man who then drove her to the Echuca police station, the Riverine Herald reported.
The woman was arrested after she presented herself to Echuca police about 10pm on Thursday.
She was admitted to hospital and received treatment for a dog bite. She has since been released.
The children were not formally in the care of their mother and were being cared for by their grandparents, the Herald has reported. Police are trying to locate each boy's father.
smh.com.au, with AAP, the Bendigo Advertiser