BURLINGTON, Vt. (AP) — The man accused of starting a fire outside independent U.S. Sen. Bernie Sanders’ Vermont office earlier this month will remain detained pending further legal proceedings, a federal judge ordered Thursday.

Shant Michael Soghomonian was indicted by a grand jury on a charge of maliciously damaging or attempting to damage and destroy by fire a building used in interstate commerce, according to the indictment filed with the court. Soghomonian, 35, has not yet been arraigned.

Surveillance video shows the man throwing a liquid April 5 at the bottom of a door opening into Sanders’ third-floor office in Burlington and setting it on fire with a lighter, according to an affidavit filed by a special agent with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives.

The motive remains unclear, and Sanders was not in the office at the time.

Seven employees working in the office were able to get out unharmed. The building’s interior suffered damage from the fire and water sprinklers.

Soghomonian, who was previously from Northridge, California, had been staying at a South Burlington hotel for nearly two months and was spotted outside Sanders’ office the day before and the day of the fire, according to the special agent’s report.

Prosecutors argued that Soghomonian is a danger to the community and a flight risk and should remain detained. A phone message was left with his public defender and was not immediately returned.