The recently demoted police chief of Banteay Meanchey province was arrested on Monday and is being held on suspicion of drug trafficking, officials said.
Hun Hean, who was removed from his position as chief on Friday, was being held at the Ministry of Interior for questioning late Monday, Khieu Sopheak, a spokesman for the ministry, said.
He was invited to the Ministry of Interior on Monday to explain accusations of drug smuggling and was subsequently seized by security police, Khieu Sopheak said.
Hun Hean's deputy, Chheang Son, was also arrested.
Hun Hean, who is not related to the prime minister, Hun Sen, was removed from his post following January 7 holiday celebrations and told local media he would report to the Ministry of Interior on Monday for a new assignment.
He has previously denied involvement in trafficking.