This is the Illinois Association of Chiefs of Police.  http://www.ilchiefs.org/  This organization hires a professional fundraising company to call and harass people for donations.  One year, I was threatened that I would be blacklisted by Police in the state of Illinois if I did not contribute.  I stated that I did contribute by paying my state taxes and then hung up on them - only to be immediately called back and threatened some more.

In response to Mel's comments above:

I would never count on the call being from the actual police organization or any organization that they use to make calls.  There are many scammers claiming the same thing.  The fact that they made threats seems suspicious.

Have you met Illinois Cops? They never met a human they didn't hate.