SA twin mentally incompetent of murder

A South Australian man charged with the murder of his twin brother will be found not guilty by reason of mental incompetence, a court has heard.

Lucas Brian Timothy Cawte allegedly shot his brother Jake on a property at Willunga, south of Adelaide, in March last year.

In the South Australian Supreme Court on Friday, the Director of Public Prosecutions conceded Cawte was not mentally competent when he allegedly committed the offence.

Justice Kevin Nicholson will be asked to formally find Cawte not guilty during a hearing scheduled for next week.

Cawte appeared by video link from James Nash House, where his counsel said he was in a rehabilitation ward in a "very stable" condition.

He is expected to seek limited supervised leave from the facility as part of his license conditions, which are yet to be decided by the court.

Previously, a court heard Cawte shot his brother twice to stop him "going to God", and intended to take his own life but instead handed himself into police.