Police said Tuesday that they questioned a Korean-American singer over his alleged sexual harassment of a cabin crew member on a U.S.-bound flight last month.

Bobby Kim, a popular R&B singer in South Korea, is accused of inappropriately touching a female crew member as well as hurling sexual insults while he was intoxicated on a flight from Incheon to San Francisco on Jan. 7.

Kim said that there was physical contact with a cabin crew member as he was asking her for her mobile phone number.

Police said they plan to refer the case to the prosecution soon.

Kim's management agency has said he had been upset when he was drinking wine as Korean Air had mistakenly seated him in economy class even though he had earlier requested a mileage upgrade to business class.

Last month, Kim was questioned by the U.S. Federal Bureau of Investigation over the incident upon landing at San Francisco International Airport. (Yonhap)