The federal officer killed while on duty near the Canadian border has been identified as a U.S. Air Force veteran who provided security at the Pentagon during the Sept. 11 attacks.

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 police incident has closed Interstate 91 in Vermont, near the border with Canada, on Monday afternoon, state police said. The nature of the police incident, with Vermont State Police called “evolving” in a statement,