Zimmerman, 29, got into a scuffle with Martin after spotting the teen while driving through his gated townhouse complex on a rainy night in February 2012. Zimmerman has claimed he fired in self-defense after Martin sucker-punched him and began slamming his head into the pavement. Prosecutors have disputed his account and portrayed him as the aggressor.
During closing arguments, de la Rionda argued that Zimmerman showed ill will and hatred when he whispered profanities to a police dispatcher over his cellphone while following Martin through the neighborhood. He said Zimmerman "profiled" the teenager as a criminal.
"He assumed Trayvon Martin was a criminal," de la Rionda said. "That is why we are here."
O'Mara's conversational tone during closing arguments was a contrast to prosecutor Bernie de la Rionda's booming closing a day earlier.
The prosecutor told the jury Zimmerman wanted to be a police officer and that's why he followed Martin. But "the law doesn't allow people to take the law into their own hands," de la Rionda said.
De la Rionda's two-hour presentation also included moments when he seemed to appeal to jurors' emotions by showing a head shot from Martin's autopsy and a face-up crime scene photo of Martin. Several jurors looked away.
Follow Kyle Hightower on Twitter at http://twitter.com/khightower.
Follow Mike Schneider on Twitter at http://twitter.com/MikeSchneiderAP.