New documents, audio and video have been released in the case against George Zimmerman who is charged with the second-degree murder of Trayvon Martin. Below are updates on statements Zimmerman made to police, made public as part of discovery, which have been released by his defense team.

[Updated at 8:14 a.m. ET] Zimmerman told police that at some point during the exchange with Martin he began hitting his head into the sidewalk.

"When he started doing that, I slid into the grass to try to get out from under him ... I'm still yelling for help," Zimmerman told investigators.

Martin, he said, put his hand over Zimmerman's mouth and nose and told him, "You're going to die tonight."

"When I slid, my jacket and my shirt came up, and when he said, 'You're going to die tonight,' I felt his hand go down my side, and I thought he was going for my firearm, so I grabbed it immediately, and as he banged my head again, I just pulled out my firearm and shot him."

When he did, he said Martin, who had been on top of him, fell away and said, "All right. You got it. You got it."

Zimmerman claimed in the interview he was driving to the grocery store February 26 when he saw Martin walking in his neighborhood. He said he pulled over and called a police non-emergency number "to report a suspicious person."

He noted there had been some burglaries in the area, prompting him to start a neighborhood watch program. He said he had never seen Martin before, and thought it was odd that although it was raining, "he was just walking casually, not like he was trying to get out of the rain."

As he spoke to the dispatcher, he said Martin circled his vehicle, but he "lost visual of him" and got out of the vehicle to find him. The dispatcher, he said, told him "we don't need you to do that," and he was heading back to the vehicle when Martin jumped out, asking him, "What the f-'s your problem?"

He said he told Martin, "I don't have a problem," but the youth replied, "Now you have a problem," and attacked him. He said he fell backward after being punched in the nose, and "he was wailing on my head."

Zimmerman told police he yelled for help repeatedly, and heard one man say he was going to call 911.

"I screamed 'Help me' probably 50 times, as loud as I could," he said.

Read Zimmerman's written statement to police (PDF)

[Posted at 7:50 a.m. ET] In an initial interview with police following the shooting death of 17-year-old Trayvon Martin, George Zimmerman described a life-and-death struggle that began when the youth "jumped out from the bushes."

Zimmerman said Martin punched him repeatedly in the face. "I started screaming for help. I couldn't see. I couldn't breathe."

He said Martin "grabbed my head and started hitting it in the sidewalk."

The audio of the Zimmerman's first interview with police investigators was made public late Wednesday as part of the discovery items released by his defense team.

Zimmerman, 28, is charged with second-degree murder in Martin's February 26 shooting death. Zimmerman has claimed he shot Martin in self-defense, but Martin's family and civil rights activists from across the country claim that Zimmerman, who is white and Hispanic, racially profiled Martin and ignored a 911 dispatcher's advice not to follow him.

Read some of the previous documents in the Zimmerman case