The convicted killers of Dean Fuller-Sandys and Leah Stephens are attempting to appeal their convictions

Open Justice reports four people are appealing their convictions in relation to Fuller-Sandys' death in 1989.

He failed to return from a fishing trip on Auckland's west coast and Police say he was shot.

One of the convicted killers, Stephen Stone, then killed sex worker Leah Stephens, who was present during the killing.

The Crown last month admitted a miscarriage of justice had taken place - after two pieces of evidence were not turned over in a 1999 trial and a re-trial a year later.

Two of four key witnesses have taken their evidence back.