DETROIT (WWJ) – There were some scary moments for airline passengers traveling from Reagan Airport in Washington D.C. to Detroit Friday when their flight was delayed due to some “suspicious behavior.”

It was Pinnacle Flight 3290, according to an airline spokesman, Eric Epperson.

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“There was a federal law enforcement officer on board who, prior to the flight pushing back from the gate for taxi observed a group of four passengers behaving suspiciously,” Epperson told WWJ Newsradio’s Beth Fisher. “He reported those behaviors to the crew and based on that, the captain made the decision not to push back from the gate.”

Epperson said all passengers were de-planed and the suspicious passengers were questioned by law enforcement and removed from the flight.

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“These are situations we take very seriously and, and again, out of an abundance of caution , you  have to make sure , particularly with a federal law enforcement agent on board , that you’re taking every precaution,” he said.

The other 70 passengers were re-boarded and headed to Detroit Metro Airport following a delay Epperson said was about two hours.

It’s not clear if the “suspicious” passengers are in custody or what became of them. They were not allowed back on the plane.

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The FBI is investigating.