Military-garbed agents in unmarked vehicles at Martinez protest

Militarized Federal agents have been seen at protests in Portand. They drive in unmarked vehicles. They have been attacking protestors, and making arrests without identifying who they are. They don't speak at all. Arrestees are not told why they arrested or what agency these agents represent. It is now known that at least one agency involved in these silent arrests is BORTAC - the Border Patrol Tactical Unit.

On Sunday July 12, there was a rally against racism in Martinez (a city in Contra Costa County, here in California). A small group of military-garbed agents were seen at the rally. Some were in a red four-door pick-up truck with no front plate. Others were in a grey minivan, similar in style to a van used in Portland by Federal agents.

One video of them was posted here on Twitter: https://twitter.com/Gillis57/status/1282505095913934848 The word "police" seems to be on the back of one of their bullet-proof vests. While it might be the first assumption to make that these are local police, it is the case that Federal agents (including Border Patrol) also use the vague term "police" on their vests as well. On the sleeve of one the agents entering the red truck, a patch can be seen. It is not readable in the video.

In this photo posted on Twitter, there is a somewhat better image of the patch on the agent entering the red truck: https://twitter.com/bigbadwulff510/status/1282525489450516480 Again though, it is not clear what agency this person works for due to the size and quality of the photo. Perhaps it is recognizable to someone reading this article.

Are these members of a local SWAT team (either police or sheriff)? Or were these agents of a Federal department such as BORTAC? Whoever they work for, they did dress differently than other police at the rally, had more gear, and they were the only ones in unmarked civilian-style vehicles.