COVENTRY, Vt. (TNND) — A U.S. Border Patrol agent shot and killed during a traffic stop in northern Vermont Monday was a veteran of the U.S. Air Force who worked security at the Pentagon during the Sept. 11 attacks, according to his family and officials.

A shooting involving a U.S. Border Patrol agent has closed Interstate 91 in Coventry, Vermont, near the border with Canada, state police said.

Agent David “Chris” Maland died in a shooting following a traffic stop, the FBI said. A second person killed in the incident was a German national in the country on a current visa, authorities said.