Kirk Mundy can't be charged with any further crimes in the Rebecca Middleton case because of a plea deal he struck 11 years ago with the Attorney General, his lawyer told a court yesterday.

Charles Richardson argued before Chief Justice Richard Ground that the agreement still stands.

Mundy agreed to testify against Justis Smith, on a murder charge, in exchange for a lesser charge of accessory after the fact to murder - a deal widely criticised in the years since because of strong forensic evidence suggesting two killers.