It has already started..

7/16/2020
Federal law enforcement officers have been using unmarked vehicles to drive around downtown Portland and detain protesters since at least July 14. Personal accounts and multiple videos posted online show the officers driving up to people, detaining individuals with no explanation of why they are being arrested, and driving off.

https://www.opb.org/news/article/federal-law-enforcement-unmarked-vehicles-portland-protesters/