A United Airlines flight from the city's O'Hare International Airport landed safely in Philadelphia after crew members found a threatening message in the plane's lavatory that said "Bomb on, will die".
The plane, an Airbus A-320 with 113 passengers and 5 crew members on board, was headed to Philadelphia International airport.
The crew found a hand-written bomb threat on a bathroom wall on the plane during the flight and notified authorities.
"A flight attendant observed writing on a wall in a rear laboratory that stated 'Bomb on, will die'," Philadelphia Police Chief Inspector Joe Sullivan said.
The flight landed safely at a secure area of the airport around yesterday night and was met by Philadelphia police, FBI and Transportation Security Administration officials.
The passengers were taken to a secure location to talk to investigators, while the crew members were taken to a separate location for questioning, according to investigators.
Luggage aboard the plane was scanned and searched by authorities, who said so far no suspicious devices or packages have been found.