Conversation so far:
what does US vs Chong refer to?
In 2003 Tommy Chong became caught up in two American legal investigations, code-named Operation Pipe Dreams and Operation Headhunter.
what was the Tommy Chong investigations regarding?
Operation Pipe Dreams and Operation Headhunter tried to trace drug traffic and users through businesses selling drug paraphernalia, mostly bongs.

Question: how was Chong involved?
Self-contained rewrite: how was Tommy Chong involved with drug traffic and users?