Philadelphia ? Federal officials defended the response of an air marshal who trained his gun on a passenger-filled jet cabin for 30 minutes after detaining a man, prompting protests by a judge who was on the flight.

Two armed marshals detained the man on Delta Flight 442, which was flying from Atlanta to Philadelphia with 183 people on board, because he allegedly was rummaging through other people’s luggage.

One marshal then held his gun on the coach cabin passengers because some of them ignored orders to remain seated with their seat belts on, a spokesman for the Transportation Security Administration said Sunday.

“If people would have stayed in their seats and heeded those warnings, that would not have happened,” said TSA spokesman Robert Johnson in Washington. “It’s our opinion that it was done by the book.”

He said the TSA, which oversees federal air marshals, was still reviewing the marshals’ response on the Saturday flight.

The man whom the marshals detained was released and the U.S. Attorney’s office decided not to press charges, said FBI spokeswoman Jerri Williams.

Philadelphia Common Pleas Judge James A. Lineberger, who was sitting diagonally across from the detained man, said he thought the marshals overreacted by holding their semiautomatic weapons on passengers for so long.

Lineberger also said he hadn’t noticed any disturbance before the marshals suddenly took the man up to first class and restrained him.

Several minutes later, the judge said, the marshals returned to the coach cabin and pulled out their guns.

“I assumed at that moment that there was going to be some sort of gun battle,” he said. “I’m looking right down the barrel of the gun as though it was pointed at me.”

Lineberger said he plans to file a complaint with the TSA on Tuesday. He said about 30 other passengers also plan to complain.