SA man jailed for murdering good friend

A man who repeatedly stabbed and slit the throat of his good friend for unknown reasons has been jailed for at least 20 years.

Barry Walter Coleman, 39, was found guilty of murdering the 33-year-old man, who cannot be named, in November 2012 at Thevenard on the west coast of South Australia.

"The circumstances of the offending and why you committed these offence are indeed a mystery," said Justice Michael David when sentencing him for life in the Supreme Court on Tuesday.

He noted Coleman had no previous convictions for any form of violence and no one suggested he was the type of person to behave in this way.

His estimated blood alcohol reading at the time of the murder was between .204 and .244, while his victim's was .299.

The pair had been drinking at a hotel when they appeared to be on friendly terms.

But sometime later, Coleman went to a relative's home and said he had stabbed his friend to death.

He took police to the death scene and said he had acted in self-defence, a claim the jury rejected.

The judge noted Coleman had an intellectual disability, which may have been exaggerated by the effects of large amounts of alcohol.

But he said it was very hard to understand the reason for the "frenzied and violent attack" which left the victim with 34 stab wounds including a slit throat.

The victim's family had been "remarkably forgiving and admirably Christian" in their attitude to Coleman, who made a heartfelt apology, the judge said.