Detective Sergeant John McPherson, 51, has been moved from Middlesbrough CID to duties "elsewhere" in the force, said a spokesman.
Earlier this month the head of Middlesbrough CID Detective, Superintendent Ray Mallon, seen as the architect of the new policing strategy, was suspended amid allegations of misconduct. He has strongly denied the claims. In October, two other detectives from the unit were suspended for allegedly supplying drugs to criminals in exchange for confessions.
The transfer of Mr McPherson, who had been with the CID for eight years and who has been a police officer for 31 years, is the first such move since Superintendent Adrian Roberts took over as new boss of the CID unit this week.
The spokesman said: "A detective sergeant has been moved from Middlesbrough CID, following the launch of an inquiry by the force's complaints and discipline branch into allegations of discipline and potentially criminal conduct."