In August 1987, Kiszko was transferred to the specialist B-Category Grendon Prison where, in June 1988, the prison governor tried to persuade him to enroll on a sex offenders' treatment programme. This would require him to admit he murdered Lesley, followed by an exploration of his motives and behaviours. Kiszko refused to take part, persistently 'refusing to address his offending behaviour' on the grounds that he had done nothing that needed addressing. Having been classed as making 'no progress' he was returned to Wakefield Prison in May 1989.
