An American Airlines flight returned to Fort Lauderdale-Hollywood International Airport shortly after taking off Monday because a threatening note was found on board, federal authorities said.

Flight 605 departed from the airport for San Juan at 6:53 p.m. It turned back when a passenger discovered a napkin with a bomb threat written on it, FBI Spokeswoman Judy Orihuela said.

A passenger found the note when they flipped down their tray table, Orihuela said. The note said "bomb" repeatedly and had "meet the parents" written in parentheses. It was discovered 30 to 40 minutes into the flight, which had 176 passengers and 6 crew members on board.

The passenger handed the note to a flight attendant, who gave it to the pilot. Passengers were evacuated from the plane by bus. BSO dogs searched the plane and the luggage. No bomb was found on board and no one was injured.

The plane returned just before 8 p.m. The FBI is investigating.