DETROIT—Detroit police Chief James Craig has ordered an internal investigation of the actions of a police supervisor who released the City Council's new No. 2 leader after he was stopped for an unidentified traffic offense, authorities said Thursday night.

Officers from the Second Precinct made a "legal traffic stop" about 10 p.m. Tuesday and learned "the individual driving the vehicle was identified as City Council President Pro-tem George Cushingberry Jr.," Detroit police said in a statement.

"As per department directives, the officers notified communications and requested a supervisor to the scene," the statement said. "Upon the supervisors' arrival and based on their observations, Councilman Cushingberry was issued a citation for a traffic related offense and released from the scene."

Cushingberry, who was elected president pro-tem Monday by the newly seated council, told the Detroit Free Press he was given a citation for not using his turn signal. The police statement didn't specify the traffic offense, but said "the chief of police has opened an internal investigation into this matter based on the supervisors' actions."

Cushingberry also told the newspaper and WXYZ-TV there was an empty rum bottle in his backseat and that a passenger who has a medical marijuana card had pot on him.

Cushingberry is a former Wayne County commissioner and won his first term on the City Council in November.

The Associated Press left telephone messages Thursday for police and Cushingberry seeking details and comment.

"I can't comment further because there may be criminal charges," police spokesman Sgt. Michael Woody told the Detroit Free Press. "We have to determine what went wrong with the way this was handled."

Asked if Cushingberry should have been arrested, Woody told the newspaper "it appears that way."