The FBI, among other three letter agencies, has been known to operate end points in the TOR network. TOR is a useful, but not entirely sufficient way to stay anonymous on the internet. If that's your goal, you have to use TOR, a good VPN, and a dedicated operating system such as TAILS. And you have to properly configure each of these at all times. Anonymity on the internet is hard, and requires careful stagecraft. And even if you do everything perfectly every time, it still might not be good enough.