It follows clashes between white supremacist group Proud Boys and Australia Day protesters.
Controversy has ramped up across the ditch over Scott Morrison's comments.
The three men were caught off guard by a large wave.
The woman was surrounded in bushland near Byron Bay, New South Wales last week.
Newshub Australia correspondent Emma Cropper explains.
Acting deputy commissioner Bob Hill said the deaths were "tragic".
"I cried on the phone and said I didn't want to do it, but there was no option, I had to."
Police have launched a homicide investigation.
Advocates have likened it to a "warzone".