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, also known as Michael Soghomonian, 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 a motive remained unclear as of Sunday afternoon.

Soghomonian entered the Church Street building Friday morning and headed directly to the third floor, where Sanders’s Vermont office is located, the U.S. attorney’s office said in a statement. Security video footage showed the 35-year-old man spraying a liquid near the door of the office, then lighting the area with a handheld lighter.

A “significant” blaze began, engulfing the door and hindering multiple staffers from fleeing, according to a statement from the Burlington Police Department. Soghomonian then fled the building.

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. Authorities responded at 10:45 a.m.

Sanders was not present when the incident occurred, according to the police department. The agency did not disclose how many staffers were in the office at the time.

In a statement, the senator said he was “deeply grateful” to local, state and federal law enforcement for responding to the fire.

“I am also thankful that none of the many people who were in the office building at the time of the fire were injured,” he added. “I appreciate the outpouring of support and well-wishes for me and my staff. We are proud to be able to continue to serve Vermonters during these challenging times.”

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 if convicted. 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, including the Burlington Police Department, the Bureau of Alcohol, Tobacco, Firearms and Explosives, Vermont State Police and U.S. Capitol Police.

Burlington Mayor Emma Mulvaney-Stanak said in a statement on Sunday that she was grateful for the collaboration, and added that her office “will continue to be in close communication as their office navigates the impacts of this incident.”