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.

Read more: Philadelphia Inquirer