SEOUL, March 20 — South Korean actor Yoo Ah-in is scheduled to appear before police later this week for questioning over allegations of illegal drug use, police officials said today.The actor, who tested positive for four banned substances — propofol, marijuana, cocaine and ketamine — in a recent forensic drug test, will undergo questioning Friday as a criminal suspect at the Seoul Metropolitan Police Agency, Yonhap news agency quoted the officials.The police investigation began after the Ministry of Food and Drug Safety said that Yoo’s prescription purchases for propofol for nonmedical purposes have been too frequent since 2021. — Bernama