On the subject of how to find out about political violence in my community, certainly there was plenty of it here in Washington DC in 2020-early 2021. That was a scary time, a bit nightmarish really, with small groups of armed people operating on the margins of larger marches and committing physical harm as well as property destruction.
Regarding violence against electoral officials in the broader DMV area, there is this interesting recent commentary from Chris Piper, the outgoing head of the Department of Elections for the state of Virginia: Elected leaders need to stand up for election officials – Virginia Mercury. He says that voter ignorance of how elections are run and the failure of elected officials to speak up clearly for the professionals who run them are both problems. These problems diminish voter confidence in elections, which can end in violence.