Looking for advice---I'd like to track down somone who threatened me online

Looking for advice on tracking down someone who threatened me online. 

I write a conservative blog on my town’s online newspaper.  A commenter wrote that I should be shot. 

I have the IP address—is there any way I can track down who sent the message?  At the very least, if I can put some heat on the Internet provider, I can make the dude’s life uncomfortable., and perhaps dissuade him (?) from doing it again.  Any ideas?

Rest assured, I know this happens a lot online…but I don’t like the idea of just sitting here and taking it.  I’d like to punch back, as much as possible.

Apologies to moderators—I tried using the “Contact” link, but I got a “Not Found” error prompt.