American Legal Services a Daniel Carter called my home and work calling himself an "officer", Internet

Received repeated phone calls from a man with Indian accent saying he was "Officer Daniel Carter" at home and work. Having been targeted by this type of scam before, I posed as someone taking a message.  

He said it was important to call back as money was owed and if payment wasn't received, an arrest was imminent. Having researched this due to prior scam, I had learned that legitimate collectors never use this sort of language.  It is illegal.

Called back, told him I knew he was a SCAM and a FRAUD and NOT to call me back!!! Of course, he starts getting angry and threatening..I simply hung up.

I'm wondering exactly where to report these slimeballs since they are probably using fictitious names, locations and numbers.  NOTE:  There is a legitimate American Legal Services that has on their webpage warnings about these scammers.