A man was arrested Sunday for allegedly lighting a fire outside the Burlington, Vt., office of Sen. Bernie Sanders (I-Vt.), authorities said.

Shant Soghomonian, 35, is charged with using fire to damage the building, according to the U.S. attorney’s office for Vermont. No injuries were reported, the office said, and Soghomonian’s motive remained unclear as of Sunday afternoon.

Soghomonian entered the building on Friday morning and headed directly to the third floor, where Sanders’ Vermont office is located, the U.S. attorney’s office said in a statement. Security video footage showed Soghomonian spraying a liquid near the door of the office, then lighting the area with a handheld lighter.

A “significant” blaze began, which engulfed the door and hindered multiple staffers from fleeing, according to a statement from the Burlington Police Department.

The fire damaged the door’s exterior, and the hallway, and set off the building’s sprinklers. The sprinkler system “largely extinguished the fire,” the police department said. Sanders was not in the office at the time, according to the police department.

Soghomonian, previously of the Northridge neighborhood in California, could face a maximum of 20 years in prison and a fine of up to $250,000. A lawyer “has not yet been identified” for him, the U.S. attorney’s office said in its statement.

Multiple agencies investigated Friday’s incident, according to the statement, including the Burlington Police Department, the Bureau of Alcohol, Tobacco, Firearms and Explosives, Vermont State Police and U.S. Capitol Police.

“I am grateful for the collaborative effort by local, state and federal partners to identify and apprehend a suspect in the arson that took place at One Church Street on Friday, April 5,” Burlington Mayor Emma Mulvaney-Stanak said in a statement Sunday, adding that her office will stay in contact with Sanders’ staff.

Sanders’ office did not immediately respond to a request for comment Sunday.

This year began with a spate of violent political threats, The Washington Post reported, which U.S. Attorney General Merrick Garland had called a “deeply disturbing spike.” While acts of physical violence toward public officials remain relatively rare, even the possibility of harm undermines the health of the nation’s democracy, experts told The Post.