What is a "coin swap" service and why are they high risk?

What I do with your dirty crypto is my own concern – such is the prompt of a Russian crypto exchanger on an illicit forum, signaling their not-so-subtle willingness to launder money for the cybercriminal underworld. In this excerpt from our recent “State of Cross-chain Crime” report, Elliptic takes a look at the empire of “coin swap” services that have processed over $1.2 billion of dirty crypto for hackers, dark web kingpins, ransomware operators and master scammers.