George Zimmerman faces second-degree murder charges.
Defense attorneys in the murder trial of neighborhood watchman George Zimmerman on Thursday will try to pick apart the testimony of a key witness who was on the phone with unarmed black teenager Trayvon Martin moments before he was gunned down.
Rachel Jeantel, 19, told the court on Wednesday that shortly before he was fatally shot last year, Martin complained about a "creepy" man who seemed to be hunting him down as he walked back to the house where he was staying with his father in the central Florida town of Sanford.
Martin family lawyer Ben Crump has said Jeantel's testimony would help undermine Zimmerman's assertion that he acted in self-defense.
Zimmerman, 29, was a neighborhood watch volunteer in the Retreat at Twin Lakes community in Sanford at the time of the killing. He has pleaded not guilty to second-degree murder and could face life imprisonment if convicted.
Martin was a student at a Miami-area high school and a guest of one of the homeowners. He was returning after buying snacks at a convenience store when he was shot in the chest during a confrontation with Zimmerman.
The racially charged case triggered civil rights protests and debates about the treatment of black Americans in the U.S. justice system, since police did not arrest Zimmerman, who is part Hispanic, for 44 days.
Prosecutors say Zimmerman profiled Martin, suspecting him of being up to no good, and killed him in an act of vigilante justice. The defense says Zimmerman was out doing his job as part of the neighborhood watch and simply trying to investigate a person he perceived as suspicious.
Zimmerman does not deny killing Martin. He says he did so only after he was attacked and Martin smashed his head repeatedly into a concrete sidewalk.
The prosecution faces a tall order to win a conviction for second-degree murder, and under Florida law must convince all six jurors that Zimmerman acted with "ill will" or "hatred" and "an indifference to human life."
Under Florida's Stand Your Ground law, which was approved in 2005 and has since been copied by about 30 other states, people fearing for their lives can use deadly force without having to retreat from a confrontation, even when it is possible.
Jurors are also likely to hear more testimony on Thursday from residents of Twin Lakes who heard or saw the struggle between Zimmerman and Martin on a dark and rainy night.
On Tuesday and Wednesday, two female neighbors described how they saw what they believed was Zimmerman sitting on top of Martin and heard the 17-year-old cry for help. But under cross-examination both women admitted they could not be absolutely certain about what they saw and heard.
Jeantel, with whom Martin had been friends since elementary school in Miami, told the court in sometimes emotional testimony that Martin tried to run away and thought he had lost the stranger, until he reappeared.
She said she heard Martin ask the man, "Why are you following me?" Then she heard "a bump," and Martin saying, "Get off, get off!" before the line was cut.
Under cross-examination, which began Wednesday, the defense questioned her credibility, noting that she lied about some peripheral aspects of her story. But the defense has so far been unable to poke holes in the key elements of what she claims Martin told her.