As police investigated the shooting of the Montgomery County Democratic Committee headquarters in Norristown, county officials on Thursday condemned the violence as an attack on democracy and party leaders said they would not stop their work.

During a visit to the committee’s headquarters Wednesday afternoon, executive director Brian Levy discovered that the building had been shot three times through its front plateglass window, according to Joe Foster, the committee’s chair.

Two bullets struck a credenza and one bullet hit a cardboard box, Foster said. It was unclear when the shooting occurred, he added, but likely took place between Tuesday night and Wednesday morning.

Foster said that the incident was “nerve-racking” but that he and his colleagues are not deterred.

“We’re going to continue to do what we do,” Foster said. “We’re going to continue to get our candidates elected, and we’re going to continue to send the message of the party. That’s our responsibility and we will continue in that vein.”

Valerie Arkoosh, chair of the Montgomery County Board of Commissioners, said her office was notified of the shooting Wednesday night and is supporting the investigation by local police.

“We don’t know when exactly it happened, but someone could’ve been seriously injured or killed,” she said. “And it is unacceptable from my point of view that someone would fire into an office where people are doing the work they have been hired to do to ensure our democracy is able to function in this country.”

The office is across the street from the county courthouse and other county offices, so surveillance cameras for those facilities are being reviewed, according to Foster.

In the meantime, the party will install its own surveillance cameras and consider other security precautions.

Foster said the gunfire comes about 10 days after the committee received an e-mailed threat from an anonymous sender. He declined to give specific details about the message but said that it mentioned the committee’s headquarters as a target of violence, though it did not mention any staff by name.

From its contents and language, Foster said, it appeared to have been sent by a supporter of former President Donald Trump.

Foster turned the letter over to investigators from the FBI, which is assisting in the investigation. Norristown Police Chief Mark Talbot said Thursday that his officers are probing the shooting itself.

“My instinct is … that there’s no threat to the public, but you don’t even feel comfortable saying that these days,” Talbot said. “Generally, we are not aware of anything that makes me believe any problems will project themselves, but I wouldn’t have predicted this earlier.”

The attack on the Norristown office was discovered around the same time as, on the other side of the country, other Democratic headquarters were being vandalized.

Scores of rioters in Portland, Ore., smashed windows and defaced the headquarters of the Oregon Democratic Party on Wednesday afternoon, in the wake of President Joe Biden’s inaugural address. Several people were arrested, but it did not seem the two events were related.