In what American Airlines CEO Doug Parker called “one of the worst displays of unruly behavior we’ve ever witnessed,” a flight attendant was hit in the face by a passenger and suffered a concussion during a flight from Rhode Island. An FBI report says a witness reported that Brian Hsu, of Irvine, California, “punched the flight attendant in the face near the lavatory.” In the FBI report it says a witness reported that Hsu “punched the flight attendant in the face near the lavatory.” The flight diverted and landed in Denver. Hsu says in the FBI report that he was returning home to California from New York after having brain surgery in another state. Hsu said he accidentally bumped a flight attendant and claimed the flight attendant then “charged at him and hit her nose against the palm of his right hand.” The flight attendant said she was struck on the head while talking to another flight attendant. After telling the passenger to sit down because the fasten seat belt sign was lighted, “the male passenger raised his arms as though he were going to stretch” but then struck her on the head, the FBI reports says. The flight attendant said she “took a defensive posture” and then he charged at her flailing his arms, the FBI affidavit goes on to say. The man started to retreat but then charged and “struck her in the face.” The flight attendant was diagnosed with a concussion after being removed from the aircraft by stretcher and she reports continuing pain in the nose, head and sinuses. 20-year-old Hsu was charged with assaulting a flight attendant and interference with flight crew.