SA attacker had plaster cast

One of three men who bashed a 36-year-old to death in Adelaide's north earlier this year had a plaster cast on his right arm, police have revealed.

Mark Boyce was repeatedly punched, kicked and stomped on by his attackers in January.

Detective Inspector Greg Hutchins says detailed analysis of CCTV footage has determined that one of the men involved had a plaster cast on his arm, a clue that may lead to a breakthrough in the case.