PSNI investigate police vehicle contracts
Police are investigating whether there was a conspiracy to ensure multi-million pound contracts for police vehicles went to one of Northern Ireland's largest car dealerships.
It is understood seven men have been questioned about possible bribery over two recent police tenders.
The chief constable of West Yorkshire police has been suspended as a result of the investigation.
He has not been arrested and is not being questioned.
Those who have been arrested and questioned include former Police Service of Northern Ireland assistant chief constable Duncan McCausland and a serving PSNI officer.
Terence Donnelly, 62, one of the owners of Donnelly Brothers, was among those questioned about a range of possible offences including bribery, misconduct in public office and procuring misconduct in public office.
Donnelly Brothers is one of Northern Ireland's biggest and best known car dealers.
Mr Donnelly has strenuously denied any wrongdoing.
His company has been a longstanding supplier of vehicles to the police and was recently awarded a multi-million pound contract for the maintenance of its fleet of cars.
In a statement, Mr Donnelly said he "strenuously denies any wrongdoing on his part in relation to the PSNI investigation into the awarding of police vehicle contracts".
The statement added: "He has co-operated fully with the investigation and expects to be completely exonerated."
Among those arrested were a serving police officer and a civilian who was head of the PSNI's transport department. In line with PSNI policy, both have been suspended from their jobs.
All seven of those arrested have been released and files have been sent to the public prosecution service.
The BBC understands that due to the complexity of the investigation it could be months before the review of those files is completed and the police are in a position to decide whether to bring charges.
The BBC understands that police are also looking into the tendering of another multi-million pound contract to armour more than 50 police cars that was awarded to Donnellys and a company based in England.
Former assistant chief constable Duncan McCausland has also been questioned.
Since retiring from the PSNI, he has worked as a security adviser to Donnellys.
He was released from police custody on Friday night, pending a file being sent to the public prosecution service.
On Friday afternoon, it was announced that the Chief Constable of West Yorkshire police force has been suspended as a result of the investigation, but he was not one of those arrested or questioned by the PSNI.