Investigators probing the scandal-hit West Midlands serious crime squad have pledged to go public if any more documents go missing.

Chief Constable Mr Geoffrey Dear ordered an inquiry into the squad after important files concerning an existing investigation went missing.

But Mr Jeff Crawford, the Police Complaints Authority official who is supervising the probe, warned that he would embarrass the force by going public if any more vanished.

He told the Express & Star: "If files or documents have gone missing, then we'll tell you. The public has a right to know."

The investigating team will order forensic examinations of some statements, interview notes and alleged confessions used in court cases.

The squad has been rocked by a series of claims that evidence against suspects has been fabricated.

Last month Birmingham father-of-three Mr Keith Parchment walked free after two years in jail for a crime he did not commit.

The Appeal Court decided that his conviction for robbery was unsafe after two handwriting experts pinpointed alleged irregularities in a police officer's notes of an alleged confession by Mr Parchment.

Mr Crawford said officers involved in the case are likely to face disciplinary action if no criminal charges are recommended.

His investigating team, will look at 738 arrests made by the squad from 1986 until it was axed a fortnight ago by Mr Dear.

Cases from before 1986 will be probed only if the team gets specific complaints or uncovers new evidence. 

But Mr Crawford said that the authority was not allowed under the Police and Criminal Evidence Act to probe matters before 1984, so the Birmingham pub bombings and Carl Bridgewater murder cases could not be investigated.

The investigation is expected to last at least a year, but an interim statement will be released before Christmas.

Mr Dear has already ordered an unprecedented purge of the force's CID - suspending two officers and moving more than 50 detectives to administrative duties.