In 1989, detectives from Avon and Somerset Constabulary, investigating the handling of the case, found significant pieces of evidence in relation to Surrey Police's handling of the Guildford Four and their statements. Typed notes from Patrick Armstrong's police interviews had been extensively edited. Deletions and additions had been made and the notes had been rearranged. The notes and their amendments were consistent with hand-written and typed notes presented at the trial, which suggested that the hand-written notes were made after the interviews had been conducted. The notes presented had been described in court as contemporaneous records. Manuscript notes relating to an interview with Hill showed that Hill's fifth statement was taken in breach of Judges' Rules and may well have been inadmissible as evidence. The information was not made available to the DPP or the prosecution and the officers involved had denied under oath that such an interview had happened. Detention records were inconsistent with the times and durations of the claimed interviews, as reported by the Surrey police.