Acting Deputy Secretary of Homeland Security Ken Cuccinelli confirmed the news that federal agents were in fact detaining people in Portland using unmarked vehicles. He stated that it was to move the detainees to a “safe location for questioning,” as well as a method to keep officers safe from the crowds.
He spoke of one incident where the agents had picked up someone under suspicion of attacking a federal officer. After questioning the gentleman, that they realized they had the wrong guy and released him.
The story actually happened, but its a non-event. They questioned him and didn't arrest him.
https://thegrio.com/2020/07/18/federal-officers-detain-protesters-in-unmarked-cars/
So.. okay I'm not saying federal officers aren't detaining people, but the video that is being shared around is bullshit.