A man who brutally murdered a woman in South Australia's Riverland last year will spend at least 22 years in prison.
The body of 53-year-old grocery shop worker Nina Starr was found in the River Murray at Loxton, in January last year.
The 20-year-old man pleaded guilty to attacking her with a large spanner, causing extreme facial and head injuries.
He has never offered any explanation for the murder.
The man has been sentenced to mandatory life imprisonment, and Justice Margaret Nyland today imposed a 22-year non-parole period.
He was on a suspended sentence for assault at the time he killed Ms Starr.
The Supreme Court heard Ms Starr was well known to locals but her injuries made her unrecognisable to those who found her.
Supreme Court Justice Margaret Nyland today said it appears he may have become enraged at police, who warned him to fix defects on his car the previous day.
Justice Nyland said he was an extremely violent man.
