I searched for hHardin, Mont news and pulled up several news stories that are current and there were no references to this mysterious police force.
I think it is BS.
cbs news has it. i just read a cbs/ap story about it. google search shows both local and national stories about this police force. here’s one:
http://www.cbsnews.com/blogs/2009/09/29/crimesider/entry5351491.shtml