If it's a mafioso bank used mostly by the mafia, then yes, absolutely, they should be investigated and shut down.
As for data, just as a first-order estimate, check out the rekt leaderboard [1] and see how many of the stories end with "and the stolen funds were routed through tornado, fin." If all crypto-adjacent crimes are reported to FBI at some point I am sure they have a much clearer statistics, but even as a civilian you can see that it's not small.
As I said, this is only a first order estimate, but even that is over hundreds of millions. I am sure the FBI has a much more detailed forensic account of tornado that they will bring up in the courts, which will then rule according to the law based on the evidence.
On the other hand, if you don't trust FBI, the law, or the courts to do the right thing, you have a different problem entirely, at which point none of what I say should matter to you.
There are at least 2 things here: 1) the laws and how they are applied and 2) what is in the interest of the people and what should the laws be?
I can trust law enforcement to do its job. Heck I might even trust it to do the right thing when it comes to gray areas / methods they use. But... I can definitely disagree with some laws. In fact, people doing something because it's law without critically thinking about it has worse consequences than disagreeing with the law.
Do you have any data to back this claim? Also, should banks be banned if their customers are doind shady things outside of using their services?