A 49-year-old police lieutenant was arrested Thursday for allegedly groping a female narcotics suspect while questioning her at a police station, Osaka Prefectural Police said.

Lt. Akiyoshi Akaike questioned the woman, 23, about 20 times by himself after she was arrested June 25 for alleged possession of cannabis, according to police. He allegedly touched her breasts during questioning sessions on three days in July.

Police said Akaike owned up to the misdeeds and they are planning to dismiss him. The case came to light when the woman reported it Sunday to a detention officer.

Osaka police say they instruct officers to keep the interrogation room door open when a male officer questions a woman. According to the woman, the door was open during the three sessions.