PC Neil Giles, of Humberside Police, was sacked after allegations that he breached the Standards of Professional Behaviour were found proved.
The legally qualified chairperson of the hearing ruled he had used the funds of a club for "his own purpose", and possessed a master interview tape when there was "no reason for doing so".
They ruled that the proved allegations amounted to gross misconduct.
The chairperson also ruled that he had accessed police systems for "a non-policing purpose".
Detective Superintendent Matt Baldwin said: “We conducted a thorough investigation into the actions of PC Giles and it was clear his actions fell well below the standard we would expect of our officers.”