I was involved in the BLM protests of 2021. The cops were legitimately pulling people off the street into unmarked, black vans. Some of the people that were grabbed were not even involved in the protests, they were just outside past the citywide curfew.
I had heard about this happening in Oregon and Washington through the ever reliable internet, but I didn't actually believe it until I saw it happen in my moderately sized Midwestern city.
It happened in Pittsburgh too. Undercovers in unmarked vans were just snatching people up off the street. Cops were shooting at people who were on their knees with their hands in the air. Someone plowed their car through a crowd of protesters on video, with the license plate and cops said there was nothing they could do.