If George Zimmerman is gearing up for a career as a stand-up comic, a crop of tomatoes is awaiting him. The 28-year-old neighborhood watchman accused of shooting and killing 17-year-old Trayvon Martin made an insensitive joke about the teen, jailhouse audio reveals.

George Zimmerman, a neighborhood watchman accused of gunning down an unarmed 17-year-old African-American, has turned himself in to the Seminole County Jail in Sanford, Fla.