According to this article in the American Thinker,
Tracy Martin was spreading that rumor:
http://www.freerepublic.com/focus/f-news/2878429/posts
We have the Serino affidavit now. It’s pages 26 & 27 in that 183 page document dump of May 17th. It suggests a manslaughter charge, and justifies that charge on the gounds I noted - Zimmerman is to blame for getting out of his truck, or, in the alternative, for not announcing his intentions.