"A new photograph obtained exclusively by ABC News showing the bloodied back of George Zimmerman's head, which was taken three minutes after he shot and killed 17-year-old Trayvon Martin, gives possible credence to his claim that Martin had bashed his head against the concrete as he fought for his life.
...The exclusive image shows blood trickling down the back of George Zimmerman's head from two small cuts. It also shows a possible contusion forming on the crown of his head. The original police report that night notes that the back of Zimmerman's head was wet, and that he was bleeding from the nose and head....
Zimmerman was treated at the scene by paramedics, then cuffed and driven in a police cruiser to the Sanford police station. He was questioned for hours and later released. In police surveillance video obtained last month by ABC News Zimmerman's wounds are not apparent, and there were no bandages on his head."