i heard it a lot that feds caught come criminals or online vendors of drugs & freeze their BTC
i am not sure how they do it ?
can anyone explain it ?
Yes. The government/feds can catch criminals, drug addicts, drug pushers, drug lords online even on the dark web for buying and or selling drugs. I think they can only freeze your bitcoin account if you're using an account from coinbase or a similar service.
How? Probably intercepted shipments. They probably have trained dogs to spot drug contained packages. Then the feds would look for similar packages and find where they're coming from. By then, they would just wait for the seller to send another package. then boom. got'em.