Do not call this guy back........he is trying to get your money

And he is likely a scammer - report the calls to the FTC, the FBI and your state's Attorney General.  Debt is a civil matter, not criminal, so no one is going to be charged, arrested or jailed.  If it is a collections agency, demand that they MAIL (not email or fax) a debt validation letter proving you owe this debt to them.  If they actually had documentation that proved this, they would have no problem sending it to you.  It is also a violation of the FDCPA to refuse to provide this documentation.  Bottom line - no debt validation letter = no debt owed.

Also let him know that you're recording all calls he makes to you so your attorney can sue HIM for multiple violations of the FDCPA.

The person using this number is a real scum bag!  Pretends that he's a law enforcement officer and he's going to file charges against people unless YOU pay him money!  BUT he's nothing but a scumbag Collection Agent!
Filthy collection company just trying to scare you into paying a long forgotten debt.  Simply a rotten freak!