Oliver Campbell's case was featured by the BBC's Newsnight programme - Credit: Archant A man living near Ipswich with severe learning difficulties who was convicted of shooting dead a shopkeeper said he was "put under pressure" to confess to a crime he didn't commit. A petition calling for Oliver Campbell's release has been signed by more than 80,000 people - Credit: Archant A reported confession during police interview was used as a key part of the evidence to convict the 50-year-old, who has lived in Suffolk ever since finishing his jail term at Hollesley Bay Prison, near Woodbridge. Yet there has long been doubt cast over his guilty verdict, with Mr Campbell’s solicitor, Glyn Maddocks, and barrister, Michael Birnbaum QC, saying: “Much of the police questioning was misleading and unfair.”