Three Thai nationals brutally murdered a 'Good Samaritan' because they were angry he had stepped in to protect his sister-in-law during a frightening confrontation and got the better of them, a court has heard.

Crown prosecutor Andrew Tinney, SC, said Luke Mitchell was repeatedly stabbed in the car park of a 7-Eleven in Sydney Road, Brunswick, and died later in hospital.

Sarud Seehaverachart and Thatiya Terdputham arrive at the Supreme Court last month. Credit:Jesse Marlow

Mr Tinney said Mr Mitchell had had the courage of his convictions to help someone in need and it tragically cost him his life.

Sarud Seehaverachart, 32, and Thatiya Terdputham, 40, have pleaded not guilty to murdering Mr Mitchell, 29, on May 24, 2009.