The police have searched an office at Policing Board headquarters and the home of the board's chairman Barry Gilligan.
The searches were carried out as part of an investigation into the role of the Housing Executive in a Belfast housing site.
The site at Nelson Street is owned by Big Picture Developments, which lists Mr Gilligan as one of its directors.
The searches were conducted by the PSNI's Organised Crime Branch.
The Housing Executive called in the police to investigate its own role in the development site in north Belfast five months ago.
In a statement, the PSNI said: "Searches have been conducted in Belfast as part of an investigation into matters concerning development land at Nelson Street in Belfast city centre.
"A number of items have been removed for examination from an office and a house."
A spokeswoman for the Policing Board said it could confirm that a search was carried out as part of an ongoing investigation.
Ulster Unionist Policing Board member Basil McCrea said the board's focus "must remain on its statutory remit" despite the investigation involving its chairman.
"Many significant issues are facing the Northern Ireland Policing Board at present, not least the finances of the PSNI and an ever worsening security situation.
"It is important that the Board remains focused and poised to address its statutory responsibilities," he said.