Fourteen former and serving police officers – including two chief constables – could face criminal charges over a botched murder probe.
A file of evidence has now been handed over to the Crown Prosecution Service following an investigation by the Independent Police Complaints Commission.
Five men were jailed for the gangland killing of drug dealer Kevin Nunes, who was gunned down in a country lane in Pattingham in 2002.
But their convictions were overturned last year following a report which detailed blunders by Staffordshire Police.
A file of evidence has been passed to the CPS in relation to five officers up to the rank of Detective Chief Inspector, who were part of the Staffordshire Police Sensitive Policing Unit, which looks after protected witnesses.
Three of the five officers have now retired from the force. A second file of evidence is expected to be submitted to the CPS in the coming weeks in relation to a further nine officers, of the rank of Superintendent and above who held senior positions in the force prior to the murder trial ending in 2008.
Four of the nine have retired and the others are still serving within police forces.
Among them are Marcus Beale, assistant chief constable at West Midlands Police, Northamptonshire chief constable Adrian Lee and Suzette Davenport, the chief constable of Gloucestershire Police.
It also includes Staffordshire’s deputy chief constable Jane Sawyers, who was formerly assistant chief constable in the force.
The IPCC investigation has considered more than 8,000 documents and taken around 300 statements. The CPS will now determine whether any criminal charges should be brought.
The men jailed for the killing of Nunes were Adam Joof, of Derwent Close, of Willenhall; Owen Crooks, of Wolverhampton; Levi Walker, of no fixed address, Antonio Christie, of Devey Drive, Great Bridge and Michael Osbourne, of Hobgate Road, Heath Town.
Their convictions were quashed by the Court of Appeal.