The Orlando Sentinel reports:
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, leaving him bloody and battered, law-enforcement authorities told the Orlando Sentinel.
That is the account Zimmerman gave police, and much of it has been corroborated by witnesses, authorities say.
The newspaper elaborates on Zimmerman’s story:
Trayvon was visiting his father’s fiancée, who lived there. He had been suspended from school in Miami after being found with an empty marijuana baggie.
. . . .
Zimmerman told them he lost sight of Trayvon and was walking back to his SUV when Trayvon approached him from the left rear, and they exchanged words.
Trayvon asked Zimmerman if he had a problem. Zimmerman said no and reached for his cell phone, he told police. Trayvon then said, “Well, you do now” or something similar and punched Zimmerman in the nose, according to the account he gave police.
Zimmerman fell to the ground and Trayvon got on top of him and began slamming his head into the sidewalk, he told police.
Zimmerman began yelling for help.
As well as the available corroborating evidence:
Several witnesses heard those cries, and there has been a dispute about whether they came from Zimmerman or Trayvon.
Lawyers for Trayvon’s family say it was Trayvon, but police say their evidence indicates it was Zimmerman.
One witness, who has since talked to local television news reporters, told police he saw Zimmerman on the ground with Trayvon on top, pounding him — and was unequivocal that it was Zimmerman who was crying for help.
Zimmerman then shot Trayvon once in the chest at very close range, according to authorities.
When police arrived less than two minutes later, Zimmerman was bleeding from the nose, had a swollen lip and had bloody lacerations to the back of his head.
http://articles.orlandosentinel.com/2012-03-26/news/os-trayvon-martin-zimmerman-account-20120326_1_miami-schools-punch-unarmed-black-teenager