WAYNE, Pa. — With the television in her pizzeria showing an endless loop of the Boston manhunt on Friday, Bessie Kontis glanced up at scenes of the quasi-military lockdown and shuddered.

“After something like that happens, they should stop all visas, for crying out loud,” said Ms. Kontis, 58, who owns New Wayne Pizza with her husband, Alex. “It’s insane. It just angers me.”

Ms. Kontis was born in Greece and immigrated to the United States as a child, but when two men of Chechen heritage were identified as the suspects in the fatal Boston Marathon bombings, her usually broad views about immigration became colored by concerns for national security.