Sean Noffke, the dispatcher who answered Zimmerman's call, is heard instructing Zimmerman to "let me know if this guy does anything else."
During the call Zimmerman can be heard grumbling "F***ing punk" and telling the dispatcher "these a**holes always get away."
At one point Zimmerman tells Noffke that Martin has started running.
"Why did you ask 'Are you following him?'" prosecutor Richard Mantel basked Noffke.
"It sounded like movement and wind coming through the phone," Noffke said.
Under cross examination Noffke said Zimmerman did not sound hostile or angry despite the epithets he used. He conceded Zimmerman may have misinterpreted his instructions or felt compelled to follow Martin.
"I want to be clear, did you hear any of that hostility in the conversation?" asked Zimmerman's lead defense attorney Mark O'Mara.
"No sir," Noffke responded.
The non-emergency call is the first key piece of evidence that was brought before the court. Prosecutors allege Zimmerman overstepped his role as neighborhood watch captain by profiling, and following Martin despite being told not to by Noffke.
The trial opened with fireworks. O'Mara argued that Martin's parents should not be allowed in the courtroom since Zimmerman's parents were on the prosecution's list of witnesses and were therefore barred from watching the proceedings.
To bolster his argument, O'Mara put on the stand Tim Tuchalski, a friend of Zimmerman who said Martin's father, Tracy Martin, had cursed at him two weeks ago. The judge dismissed the argument.
In opening statements, prosecutor John Guy told the jury of six women, "George Zimmerman did not shoot Trayvon Martin out of self-defense. He shot him for the worst of all reasons, because he wanted to."
Zimmerman's lawyer Don West told the jury that he objected to repeated descriptions of Martin being an unarmed teenager, saying he armed himself with concrete when he allegedly slammed Zimmerman's head against the pavement.
At one point, a tape of a 911 call was played and screams for help could be heard in the background. Trayvon Martin's father wept and his mother stormed out of court while the tape was played.
Prosecutors claims that was Martin yelling for help, but Zimmerman claims those screams for help came from him.