Gun magazine found on Frontier Airlines flight, passengers forced to deplane

Passengers on a Frontier Airlines flight were forced to deplane at the gate Sunday evening in Denver after an ammunition magazine was found on the aircraft as it was preparing for departure, according to the airline. 

Frontier says preliminary investigation indicates the magazine belongs to a law enforcement officer who may have left it behind on a previous flight.

There were no injuries, officials said. All passengers were deplaned and rescreened out of precaution, and the plane also went through a security sweep, and nothing additional was recovered from the flight, according to the airline.

Flight 4765 was scheduled to travel from Denver to Phoenix. Due to the delay, the flight crew exceeded their duty time, and passengers were booked on another flight, which departed Monday morning, according to Frontier Airlines.  

TSA says it is aware of the incident, and the FBI is leading the investigation.