John Preece

Years in prison:
Year of crime:
Year conviction was overturned:

John Preece was convicted of the murder of Helen Will. Preece was a lorry driver and was said to have strangled Will in a lorry. The primary evidence against Preece was forensic evidence relating to blood, hairs, fibres, and semen. On appeal, this scientific evidence was shown to be of questionnable quality. For example, the expert had not given evidence about the victim’s blood group and had not disclosed that stains he had tested were not isolated seminal stains but mixed seminal and vaginal stains. This called into question the validity of his conclusions. As such, the forensic evidence was discredited and the conviction was quashed.

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  • Offence: Murder
  • Jurisdiction: Scotland
  • County: Unknown 
  • Ethnicity: Unknown
  • Gender: M
  • Years in prison: 8
  • Offence convicted of: Murder
  • Year of crime: 1972
  • Year of initial conviction: 1972
  • Year conviction was overturned: 1981
  • Age when imprisoned: Unknown
  • CCRC Referral: N
  • Tried with others: N
  • Link to full case: Not available
  • Type of fresh evidence at appeal: Evidence undermining forensic science
  • Compensation: Unknown
  • Crown argued case at CofA: Unknown
  • Retrial: Unknown
  • Previous appeals: Unknown