The U.S. Border Patrol agent who was slain in Vermont during a traffic stop near the Canadian border on Monday was the agency’s first agent to be killed in the line of duty since 2014.

David Maland, 44, was a military veteran who worked security duty at the Pentagon during the Sept. 11 attacks, his family said.

U.S. Border Patrol agent David “Chris” Maland and his K9 partner, Cora, in an undated photo. Joan Maland via Associated Press

“He was a devoted agent who served with honor and bravery,” the family said in a statement provided to The Associated Press late Tuesday. “He had a tremendous respect and pride for the work he did; he truly embodied service over self.”

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 hospital.

The violence temporarily closed part of Interstate 91 about 20 miles from Canada in Coventry, part of the small, 27,000-resident community of Orleans County in the Northeast Kingdom region of Vermont along the international border.

Maland had many chances for promotion but turned them down to stay in the field, said a cousin, Minnesota state Rep. Krista Knudsen. She paid tribute to the Minnesota native, who went by Chris, on the House floor Wednesday before lawmakers observed a moment of silence.

“He will be remembered for his courage and commitment to protecting fellow Americans,” said Knudsen, a Republican from Lake Shore. “He is also a person who served faithfully with honor and bravery. He always put his service above himself.”

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 of international boundary with Canada.

The Derby Line-Rock Island Border Crossing is located about 12 miles 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.

Maland’s family said his career spanned nine years in the military and 15 in the federal government. On Sept. 11, 2001, his duty station was the Pentagon, and when news of the terrorist attacks broke, he was sent to guard an undersecretary to one of the branches of the military for several days at a bunker at Joint Base Anacostia-Bolling, in southeast Washington.

Maland also was a K-9 handler who he served in Texas, near the border with Mexico, before heading to the northern border. His aunt Joan Maland said he was about to propose marriage to his partner.

“We are all devastated,” she said in a text, calling him an “exceptional person. Incredible man.”

Knudsen said she and Maland both grew up in Fairmont, Minnesota, where he graduated from high school in 1999.

“Chris was an incredible man and will be missed dearly. I am grateful for his service and I know he was very proud of it,” she said. “Our family is heartbroken. He died in the line of duty, serving to protect our country. We will cherish his memories and mourn his sacrifice. Until we meet again, Godspeed, you good and faithful servant.”

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 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. And Border Patrol Agent Isaac Morales was fatally stabbed while off duty in 2017 in Texas.