The Independent Police Complaints Commission is to investigate whether officers ordered the destruction of documents which caused the collapse of a multimillion-pound police corruption trial.
Ten defendants, including eight former officers, were acquitted of fabricating a case which led to the wrongful imprisonment of three men, known as the Cardiff Three, for the murder of Lynette White.
The case collapsed following claims that files of evidence had been shredded, but the documents were later discovered in the hands of South Wales Police. During the trial, it was wrongly alleged that a detective had ordered the destruction of papers relating to complaints made by one of the men first accused of the murder. Mr Justice Sweeney discharged the jury telling them the accused could not get a fair trial. The revelation prompted the Director of Public Prosecutions to order a review of the case.
The IPCC's commissioner Sarah Green said the inquiry was "a tightly focused investigation that concentrates on the alleged destruction of the documents".