This is a fundraising arm for one of the Law Enforcement organizations. They do not leave messages, HOWEVER, if you call them back and request to be taken off their call list, they'll do just that. Seems to be pretty decent guys, so exhibit a modicum of professionalism, please. :)
Got a call from this number at 7 p.m. Saturday night. Sorry, but I don't see that as "decent," calling up strangers on their unlisted private home numbers to ask for money!