George Hamilton, and other senior Police Service of Northern Ireland officers are subject to the probe by the region’s police ombudsman. The PSNI “completely refutes” all allegations.
The claims relate to how the PSNI handled an inquiry into the awarding of a contract to supply vehicles to the force.
Former West Yorkshire chief constable Mark Gilmore, a former PSNI officer, and retired PSNI assistant chief constable Duncan McCausland were among nine people interviewed by detectives in the 2014 investigation into bribery and misconduct in public office.
No charges were brought against any of the men, who all deny wrongdoing.
Mr Hamilton, deputy chief constable Drew Harris, and assistant chief constable Mark Hamilton are being investigated by ombudsman Michael Maguire. Less senior officers are also under investigation.
Dr Maguire has received complaints from a number of those investigated in the vehicle contracts probe in 2014, including Mr McCausland and Mr Gilmore. It is understood the claims include allegations that police documents were altered.
The PSNI issued a lengthy statement denying wrongdoing.
“PSNI can confirm that a number of senior officers, including the chief constable and deputy chief constable, have been informed of complaints made against them by former senior PSNI officers,” said a spokeswoman.
“The complaints relate to allegations of misconduct by senior police, during a criminal investigation by the PSNI into the two complainants, former senior colleagues, during 2014.”
The PSNI said it acknowledges the need for the Office of the Police Ombudsman to investigate these allegations and that all officers are co-operating with the investigation.
“The chief constable, deputy chief constable, and other officers, completely refute the allegations made against them and are strongly of the view that these complex investigations into the complainants were conducted with professionalism and integrity,” it said. “This position has been fully outlined in the officers’ initial response to Oponi [Office of Police Ombudsman for Northern Ireland].
“Whilst, ordinarily, the Police Service would limit its responses on matters where it is under investigation, this case has particular and unusual aspects to it. This case has been the subject of recent speculative press and media coverage, which has the potential to negatively impact on public confidence in policing.”
The ombudsman’s office said its investigation would be treated as a “critical incident” — its outcome could have a significant impact on the person making the complaint, on the police, or on the wider community.
“The Police Ombudsman’s Office has begun an investigation into concerns about the way in which the PSNI conducted an investigation into allegations of bribery and misconduct in public office in 2014,” said a spokesman.
“A team has been set up to look into these matters. It includes six investigators and has access to external legal advice. Given that some of the officers are above the level of chief superintendent, the Policing Board [the PSNI’s independent oversight body] has been notified.
“The office has not recommended the suspension of any of the police officers concerned.”