Officials say a Delta Air Lines flight from Reagan National Airport near Washington was held at the gate after a federal law enforcement officer on board reported to the flight crew that four passengers were acting suspiciously.
Flight 3290 to Detroit Friday afternoon was aboard a Pinnacle Airlines regional jet. Pinnacle spokesman Eric Epperson says the captain decided to stay at the gate and all passengers were ordered off. The four suspicious passengers were questioned and removed.
The rest of the 70 passengers and four crew members were allowed back aboard and headed for Detroit after a nearly four-hour delay.
The FBI is investigating but released no further information.