By Ian Bush

PHILADELPHIA (CBS) – A passenger on Thursday morning’s Philadelphia to Dallas flight that was returned to PHL (see related story) tells KYW Newsradio the pilot initially told people on board that he had some instrument problems and had to turn back.

Adrian Banica posted a picture on Foursquare from his seat on the grounded plane showing three police SUVs and a cop with a K9.

He tells KYW Newsradio by email that once the pilot landed, he “taxied to an area away from the terminal where there were bomb squad cars and fire trucks.”

PHOTOS: From The Scene

“Supposedly mechanics were going to come on,” he writes, “but about six SWAT guys jumped on a guy in the middle of the plane.”

Once they landed, passenger Steve McNeal of Milton, PA says officers came into the cabin with guns drawn.

“They told everybody not to move and put their hands on the seat in front of him,” he says.

McNeal was sitting next to the guy the agents were looking for — a man he says was confused but cooperative.

“I think he might have said what the heck, or whatever explicit word he used,” McNeal recounts.  ”They just grabbed him and pulled him up out of the seat and walked him out to the back and took care of business outside.”