Chandler Search AKA John Chandler Abusive nut case harassing me, threatening my livelihood and my client's Phoenix Arizona

I didn't even realize that this local nutcase was one of my 2,000 LinkedIn connections until today, but he emailed me via my client's business email, inviting me to a Tea Party event. He used his business email. I declined politely, at which time he responded viciously, calling me a racist and saying I voted for Obama because he was black. (what THAT had to do with anything, even were it true, is beyond me). I advised him that this was my client's business address and to unsubscribe me. He emailed me again, inviting me to another event. I again asked to be unsubscribed, after which he emailed that I cared about nobody and he hoped my business would go down in flames. He then emailed my client that I had a poor attitude and because of that he was going to tell everyone he knew nationally to boycott them. It was kind of stupid, actually, because it was clear he didn't know what kind of business they were in - hadn't even gone to their website to figure that out. 

He seems not so much a thief as a complete nut case - I mean, he's unhinged to be doing this via his business email. It makes you wonder if he's going to become violent at some point.