SAN DIEGO â€"  A recent parolee snuck onto a flight without a ticket at San Diego's Lindbergh Field Tuesday, Fox 5 reports.

38-year-old Marc Rory Duncan, who was reportedly just released from jail on Monday, was able to walk through a fire door onto the tarmac, drop off a bag and board the flight to Los Angeles, passenger Nicholas Blasgen told Fox 5.

Duncan set off an alarm when he went through the emergency door, and was caught on camera. However, once inside the plane he was able to blend in with other passengers and take a seat.

The plane's crew realized something was wrong when they did a head count and saw it was off. Flight attendants found Duncan on the flight and he was arrested without incident after police and K-9 units stormed the plane.

"It was quite an ordeal," Blasgen told Fox 5.

Airport authorities said Wednesday they are working with the TSA to investigate the incident. The TSA says they are examining whether employees at the Southwest Airlines terminal failed to properly monitor the doors.

TSA officials and the airport told Fox 5 it is not unusual for the alarm on the exit door to be set off because people  "routinely" walk through fire exit doors accidentally.  

Duncan reportedly told other passengers he was trying to get to Alaska to see family. He was charged with two counts of trespassing.

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