GRESHAM, Ore. - The Oregonian reports that the police union has filed a formal grievance against the Gresham Police Department Friday over a hidden camera placed in a work area.

Police employees discovered the pinhole camera in late February. The Gresham Police Officers Association attorney says it was placed in the ceiling by police administration to conduct surveillance after an employee complained about hostile notes left on a computer, a desk and the employee's car.

The attorney declined to identify the target, but indicated the hidden camera was found in a locked sergeant's office, which both male and female employees use to change their clothes.

The union contends that the city violated the disciplinary terms of its contract and may have violated state and federal law by failing to obtain a search warrant.

Meanwhile, some of its roughly 120 members are upset at the thought they may have been videotaped in a state of undress.

Police Chief Carla Piluso confirmed that a camera was placed to determine if there was unusual behavior and whether a criminal investigation was needed.