Authorities on Tuesday were investigating a fatal shooting of a U.S. Border Patrol agent that also left a suspect dead and another injured on a Vermont highway near Canada, authorities said.

Agent David Maland was killed Monday afternoon following a traffic stop, a U.S. Customs and Border Protection spokesperson said in a statement. A German national in the country on what the FBI called a current visa was killed and an injured suspect was taken into custody and is being treated at a local hospital.

The violence temporarily closed part of Interstate 91 about 20 miles (32 km) from Canada in Coventry, part of the small, 27,000-resident community of Orleans County in the Northeast Kingdom section of Vermont that straddles the international border.

Maland, whom the FBI confirmed was a U.S. Air Force veteran, was killed close to the U.S. Customs and Border Protection’s Newport Station, part of the Swanton Sector that he was assigned to. The sector encompasses Vermont, parts of New York and New Hampshire, and includes 295 miles (475 kilometers) of international boundary with Canada.

The Derby Line–Rock Island Border Crossing is located about 12 miles (19.3 kilometers) by highway north of Coventry. It’s a major link to the Canadian province of Quebec, giving northern Vermont more French speakers than most of New England.

“U.S. Customs and Border Protection’s thoughts and prayers are with Agent Maland’s family during this difficult time,” the agency said in a statement. The death is a tragedy, said Gov. Phil Scott and state Sen. Russ Ingalls, a Republican who represents the area.

Vincent Illuzzi, the state’s attorney in neighboring Essex County, drove past what appeared to be a U.S. Border Patrol agent traffic stop on I-91 past the Newport exit Monday afternoon, he said, shortly before authorities reported the shots were fired.

“I’m heading down the road, not much traffic, and I saw them on the right,” he told The Associated Press by phone Tuesday.

The agent was driving an unmarked white pickup trick with a cab on it and red and blue flashing lights, he said. The stopped vehicle appeared be a small, blue car, he said. The agent was speaking with someone standing in front of his truck, behind the car, he said.

“Nothing unusual at that point,” Illuzzi said, but when he got back on the highway later that night, it looked like the same two vehicles were still parked and other law enforcement vehicles had arrived.

Illuzzi said the U.S. Border Patrol works closely with state and local police in his county. “We have limited law enforcement and they’re often primary responders in emergency cases.”

Maland was the first Border Patrol agent to be killed in the line of duty since Javier Vega Jr. was shot and killed near Santa Monica, Texas, in 2014, according to records provided by U.S. Customs and Border Protection. Vega was initially considered to be off duty at the time of his death, but in 2016 it was re-determined to have been in the line of duty, the agency said.

In 2010, Brian Terry ‘s killing exposed the botched federal gun operation known as “Fast and Furious.” Border Patrol Agent Nicholas J. Ivie, of the Brian A. Terry Border Patrol Station, was mortally wounded in the line of duty in a remote area near Bisbee, Arizona, in 2012. Border Patrol Agent Isaac Morales was fatally stabbed while off duty in 2017 in Texas.

U.S. Customs and Border Protection said it would provide an update later this week. The Vermont State Police and Orleans County state’s attorney’s office declined to comment Tuesday.

Vermont’s Sen. Bernie Sanders, Sen. Peter Welch and Rep. Becca Balint sent condolences to the agent’s family in a joint statement and said Border Patrol agents “deserve our full support in terms of staffing, pay and working conditions.”