R&B singer Bobby Kim was investigated by the FBI for allegedly causing a disturbance and sexually harassing a flight attendant on an international flight, local media outlets reported Friday.

The 41-year-old, who seemed intoxicated, started shouting at the crew five hours after the Korean Air flight left Incheon for San Francisco at 4:40 p.m. on Wednesday, reports said.

Creating a ruckus, the U.S. citizen forcibly cuddled the flight attendant, touched her arms and verbally abused her for about an hour, according to news reports.

Korean Air filed a complaint against Kim, and the FBI brought him in for questioning when he arrived at the San Francisco airport at 10:13 a.m. on Wednesday, San Francisco time.

Two other crew members and two passengers who sat next to Kim were also questioned.

In response to the news reports, Kim’s label Oscar Entertainment released a statement on Friday saying that the singer was irritated before boarding the plane.

“Kim drank some wine on the flight after he got distressed by Korean Air,” the agency said. According to Kim’s agency, Kim requested his economy class seat to be upgraded to business class, but Korean Air failed to do so by mistake.

“He does not exactly remember what mistakes he made,” it added.

According to the Tokyo Convention, which governs offenses and other acts that occur on board aircraft inflight, Kim’s alleged misconduct is subject to the jurisdiction of both the U.S. and Korea, the country where the air carrier is registered.

The singer is currently in San Francisco for further questioning.

Korean police are scheduled to launch a probe into the case once he returns to Korea.

By Ock Hyun-ju (laeitica.ock@heraldcorp.com)