Trayvon Martin Shooter Told Cops Teenager Went For His Gun.

By MATT GUTMAN and SENI TIENABESO

George Zimmerman, the neighborhood watch crime captain who shot dead 17-year-old Trayvon Martin, originally told police in a written statement that Martin knocked him down with a punch to the nose, repeatedly slammed his head on the ground and tried to take his gun, a police source told ABC News.

Zimmerman had claimed he had called police about Martin, whom he found suspicious, then went back to his car when Martin attacked him, punching him.

The new information is the most complete version yet of whatZimmerman claims happened on the night of Feb. 26 when he shot and killed the teenager.

In addition, an eyewitness, 13-year-old Austin Brown, told police he saw a man fitting Zimmerman's description lying on the grass moaning and crying for help just seconds before he heard the gunshot that killed Martin.

The initial police report noted that Zimmerman was bleeding from the back of the head and nose, and after medical attention it was decided that he was in good enough condition to travel in a police cruiser to the Sanford, Fla., police station for questioning. He was not arrested.