I've done some more research and these guys are calling from lots of different numbers! The number they called me from must be new because I could only find a couple complaints. 415-3735261.  But it's always the same drill, same thick mid-eastern accent, American name with threats of imprisonment, etc.  The guy who called me said he was from "Legal Restituion Division" and called himself Jimmy Richards.  Wouldn't send anything in writing.  Wouldn't give me his address.  When I told him this was a scam and I was going to report them, he quickly ended the call.  DO NOT PAY THESE PEOPLE!  THIS IS A SCAM!  FILE A COMPLAINT WITH THE AG, FBI AND FTC.

These guys were featured on 60 Minutes.  They got their information by hacking into Internet sites, and they threaten lawsuits against the last 4 digits of your Social Security Number.  They speak with an Indian accent, and they claim you will face "harsh legal action" unless you send them between $500 and $1,000.  They are total idiots because their name does not even make sense:  United Investigation Bureau Department.

They use names like Roger Smith and Jack Jones, but their real names are probably something like Mahamanda Yogananda.  They can barely speak English.

They use various call back numbers including 347-844-6701 and 718-766-7916.

The best idea so far was what Paybackisabeatch suggested.  Turn the tables on them.  Call them back, ask for Habib, waste their time so that they cannot make money with scam calls to extort money from honest people who may get frightened or confused.