I do believe eliminating Antifa is a priority of the Justice Dept and Trump. Trump is pissed and it's pay back time.
Well, that may be. But attempting to covertly surveille them, capture some of them, & eventually try them in court for some lesser crime than real terrorism is going to be a long, as in years long, & mostly fruitless exercise.
Other avenues would prove much more effective in the short term.
MM