With a single punch, Trayvon Martin decked the Neighborhood Watch volunteer who eventually shot and killed the unarmed 17-year-old, then Trayvon climbed on top of George Zimmerman and slammed his head into the sidewalk several times, leaving him bloody and battered, authorities have revealed to the Orlando Sentinel. That is the account Zimmerman gave police, and much of it has been corroborated by witnesses, authorities say. Zimmerman has not spoken publicly about what happened, but that night, Feb. 26, and in later meetings he described and re-enacted for police what he says happened. In his version of events, he had...