A former Scotland Yard officer has been bailed by the Independent Police Complaints Commission after his arrest over allegations of unauthorised leaks to a journalist.
DCS Dave Cook, 52, was questioned on suspicion of misconduct in a public office after being detained at his Berkshire home on Tuesday morning.
He was arrested after the IPCC was passed information in mid-December by Metropolitan police detectives working on Operation Elveden, which is investigating alleged payments to police officers by newspapers.
Investigators working for the police watchdog have powers of arrest when carrying out an independent investigation. It is not clear why the Met did not carry out the arrest and instead passed the inquiry on to the police watchdog. A spokesman for the Met would not comment.
Cook has complained he was a victim of the News of the World when he was followed during his investigation into the murder of Daniel Morgan. He now becomes a potential victim of one police inquiry – Weeting – and a suspect in another – the IPCC inquiry.
Cook was criticised by the judge in the Morgan murder trial for misbehaviour in the way he handled a key supergrass witness. He was accused of allegedly coaching the supergrass, in order that his lies were not discovered.
The move comes as the Met adopts a new policy towards the media that threatens officers who maintain informal contacts with journalists, and who pass on information that is not authorised, with arrest and disciplinary action.
The new policy, outlined by Elizabeth Filkin, the former parliamentary commissioner for standards, in her report last week encourages the Met to take a tough stance against officers who leak information to journalists. Filkin said the tougher action against unauthorised leaks was part of a policy of openness and transparency. She also called for whistleblowing to be a rarity so that the Met can protect its image and reputation.
A spokeswoman for the IPCC said: "A 52-year-old man, a former Met officer, was arrested by the IPCC at his home in Berkshire this morning on suspicion of misconduct in public office and Data Protection Act offences. The arrest is the result of information passed to the IPCC by the Metropolitan Police Service team investigating Operation Elveden and relates to the alleged passing of unauthorised information to a journalist."
Nine suspects have been arrested as part of Operation Elveden, which was launched after officers were handed documents suggesting News International journalists had made payments to officers.
Sir Paul Stephenson, the then Met commissioner, said in July evidence from the publisher suggested a small number of officers were involved.
Last month, a 52-year-old woman, understood to be a member of the force's specialist operations branch, which runs Royal Protection officers, was arrested on suspicion of receiving illegal payments.
Others questioned as part of the inquiry include former News International chief executive Rebekah Brooks, ex-Downing Street communications chief Andy Coulson, former News of the World managing editor Stuart Kuttner, the paper's former royal editor Clive Goodman, and a 63-year-old man whose identity has not been disclosed.
The Met believe the final total of people whose phones could have been hacked by the News of the World will be about 800.