Detectives investigating the awarding of a number of Police Service of Northern Ireland (PSNI) vehicle contracts have arrested a 54-year-old member of police staff in County Antrim, according to reports.
He is being questioned on suspicion of misconduct in public office.
Seven men have previously been arrested as part of the investigation, including former assistant chief constable Duncan McCausland, reports the BBC.
Causland said he "strenuously denies" any wrongdoing.
Police have said files on all seven men are being prepared for submission to the Public Prosecution Service.
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.