The word Vigilantes might (or might not) have historic nuances that you (or them) may find unfortunate.

From [1] Vigilante: a member of a volunteer committee organized to suppress and punish crime summarily (as when the processes of law are viewed as inadequate) broadly : a self-appointed doer of justice

[1] https://www.merriam-webster.com/dictionary/vigilante [2] https://www.forbes.com/companies/chainalysis/ [3] https://www.coindesk.com/crypto-forensics-firm-chainalysis-a...