Zimmerman trial kicks off with opening arguments

SANFORD, Fla. -- George Zimmerman was fed up with "punks" getting away with crime and shot 17-year-old Trayvon Martin "because he wanted to," not because he had to, prosecutors argued Monday, while the neighborhood watch volunteer's attorney said the killing was self-defense against a young man who was slamming Zimmerman's head against the pavement.

The prosecution began opening statements in the murder trial with shocking language, repeating obscenities Zimmerman uttered while talking to a police dispatcher moments before the deadly confrontation.

The defense opened with a knock-knock joke about the difficulty of picking a jury for a case that stirred nationwide debate over racial profiling, vigilantism and Florida's expansive laws on the use of deadly force.

"Knock. Knock," said defense attorney Don West. "Who is there?" "George Zimmerman." "George Zimmerman who?" "Ah, good. You're on the jury."

Zimmerman, 29, could get life in prison if convicted of second-degree murder for gunning down Martin on Feb. 26, 2012. The case took on racial dimensions after Martin's family claimed that Zimmerman had racially profiled Martin and that police were dragging their feet in bringing charges.

Zimmerman, whose mother is Hispanic and whose father is white, has denied that race was a factor.

Prosecutor John Guy's first words to the jury recounted what Zimmerman told a dispatcher in a call shortly after spotting Martin: "------ punks. These -------. They always get away." Zimmerman was profiling Martin as he followed him, Guy said.

West told jurors a different story: Martin sucker-punched Zimmerman and then pounded his head against the concrete sidewalk, and that's when Zimmerman opened fire.

Showing the jury photos of a bloodied Zimmerman, West said, "He had just taken tremendous blows to his face, tremendous blows to his head."