Review into West Yorkshire Police murder case corruption
An urgent review has been ordered into the conduct of police in West Yorkshire who took a murder trial witness to a brothel and allowed him to take drugs.
Supergrass criminal Karl Chapman was given special treatment because he was the main prosecution witness.
The Supreme Court found some officers took part in a "prolonged, persistent and pervasive conspiracy to pervert the course of justice".
The police authority said it would look at the conduct of officers involved.
The Supreme Court judgment, published in July, revealed the "variety of wholly inappropriate benefits" bestowed on Chapman by officers, also included having sex with a policewoman and socialising at officers' homes.
Violent crimes allegedly committed by Chapman were also ignored by the force.
He received special treatment because he was the main prosecution witness in the case of Paul Maxwell.
Maxwell and his brother, Daniel Mansell, were originally found guilty of an attack on 85-year-old Joe Smales in Wakefield in 1996 after a Leeds Crown Court trial in 1998 which was based largely on the evidence of Chapman.
However, the convictions were quashed by the Court of Appeal in 2009 on the grounds they had been "procured by gross prosecutorial misconduct".
But at Leeds Crown Court in June, Maxwell pleaded guilty to the murder of Mr Smales and was jailed for seventeen-and-a-half years.
The force's handling of the case is now subject to an internal inquiry by the police authority.
Councillor Mark Bruns-Williamson, West Yorkshire Police Authority chairman, said: "Members of the authority want to know exactly who did what - and that means separating fact from unproven allegation and rumour.
"We have agreed as a matter of urgency to look at the conduct of any and all officers involved in this case.
"We have established a scrutiny sub-group of our audit and risk committee to ensure we monitor progress very closely."
Mr Burns-Williamson said deputy chief constable David Crompton would be conducting a review of the issues.
He said: "Although this case occurred many years ago, I will also be seeking assurances from the force that nothing like this could ever happen today and that harsh lessons have been learned."
The case has also been referred to the Independent Police Complaints Commission, which is currently considering the scope of its investigation.