Kevin Nunes investigation: Detective 'abused' overtime during botched murder case

The officer, whose name has been removed from the document, claimed more than £17,000 in extra payments during a single year and £15,310 in the following eight months.

The details are contained in a 'management review' of Staffordshire Police's Sensitive Policing Unit (SPU) which handled protected witnesses in the Nunes case.

The 73-page report was published yesterday after a year-long Freedom of Information battle by the Express & Star.

The document contributed to the murder convictions of five Black Country gangsters being quashed after it was revealed it had never been disclosed to lawyers, the jury or judge at the original murder trial in 2007.

It reveals concerns raised by former Detective Inspector Joe Anderson, head of the SPU, with then-Superintendent Jane Sawyers (now Chief Constable), over the 'management of witnesses' in the Nunes case, as well as the handling of police informants, and 'unacceptable practices employed by some officers when claiming expenses'.

Parts of the review, which became known as the Costello Report, have been removed by Staffordshire police to protect 'personal or operational' details.

• Police chief: Some officers' conduct during inquiry 'did not meet high standards of force'

The report said the DC claimed £17,751.65 overtime in 2005/06 and £15,310 between April and November 2006.

The report also confirmed details previously revealed by the Express & Star that detectives accompanied the Nunes' case star witness to bars and drunk alcohol with him, that detectives failed to record the fact the witness stole £320 of police funds, and that a detective had stayed at hotels with another officer he was having an affair with while on protected witness duties.

Others described him as 'disruptive', 'egotistical', and 'not an asset'.

The report's author, former Superintendent Joe Costello said there was no evidence to support the abuse but not a single Detective Constable in the unit thought he should remain on the Sensitive Policing Unit.

His report stated: "Although there is no evidence to support the inappropriate claiming of expenses and overtime, due to the very nature of the work a greater degree of trust and responsibility is placed upon the officers posted to the Sensitive Policing Unit.

"In this area there is always the opportunity to manipulate opportunities for personal financial gain."

Deputy Chief Constable Nick Baker said: "The content of the report shows that the actions of some of those in the Unit ten years ago is not one that now, or at the time, met the high standards we expect of officers and staff working for Staffordshire Police.

"Any mistakes or misconduct were of a professional, not criminal nature, and tackled according to the force's disciplinary process, as set out in the review."