DAVID GREENE, HOST:
In Sanford, Florida, lawyers for George Zimmerman presented witnesses yesterday. They backed up Zimmerman's claim that he was acting in self-defense when he shot and killed teenager Trayvon Martin. Several people identified Zimmerman as the person heard screaming for help in a 911 call. And the defense got another boost yesterday. The judge ruled that the jury can hear evidence of drug use by Trayvon Martin.
Here's the latest from NPR's Greg Allen.
GREG ALLEN, BYLINE: The fact that Trayvon Martin had a small amount of THC - the active ingredient in marijuana - in his system the night of his confrontation with George Zimmerman has been known for some time. It was included in the toxicology report done as part of his autopsy. Prosecutors argued it wasn't relevant to the case because Zimmerman had no knowledge of the 17-year-old's drug use when he began following him.
Also, the medical examiner who performed the autopsy, Dr. Shiping Bao, said the amount of THC in Martin's system was too small to have had an effect. Because of that, Judge Debra Nelson ruled the toxicology report off limits in opening statements.
But last week, Dr. Bao said he's changed his mind, that it's possible the small amount of THC in his system may have affected Martin. And in court yesterday, Zimmerman's defense lawyer Donald West asked the judge to reconsider.
DONALD WEST: We have testimony that we'll offer through our expert witness that the level of THC in Mr. Martin's system is sufficient to cause some level of impairment.
ALLEN: Judge Nelson ruled the jury can hear about the toxicology report and Martin's marijuana use. For Zimmerman, it was perhaps the biggest win on a day in which a series of witnesses bolstered his story that he was being beaten by Martin and feared for his life when he pulled his gun and shot and killed the teenager.
The Defense called as a witness the owner of a gym in Sanford, Adam Pollock. Pollock said Zimmerman trained at his gym for nearly a year, learning boxing and wrestling moves. But Pollock says even after all that training, he was still far from athletic.
ADAM POLLOCK: He was an overweight, large man when he came to us, and a very, very pleasant, a very nice man, but physically soft. He was predominantly fat, not a lot of muscle, not a lot of strength.
ALLEN: But the most powerful testimony once again centered around a key piece of evidence: a 911 call recorded that night in which someone is heard repeatedly screaming for help. Last week, Trayvon Martin's mother and brother testified it was their son and sibling calling for help. The defense countered by producing several witnesses who said it was Zimmerman. And the defense called back the former lead investigator in the case, Sanford Police Officer Chris Serino, who testified last week for the prosecution.
Just days after the incident, Serino played the 911 call for Martin's father, Tracy. In court, Zimmerman's lawyer, Mark O'Mara, asked Serino about it.
OFFICER CHRIS SERINO: I inquired if that was, in fact, his son yelling for help.
MARK O'MARA: And what was his response?
SERINO: He - it was more of a verbal and non-verbal. He looked away, and under his breath, as I interpret it, said no.
ALLEN: Serino said at least one other police officer heard Tracy Martin's reaction to the recording. But Tracy Martin was also in court yesterday, and he told a different story.
TRACY MARTIN: I kind of pushed away from the, away from the table and just kind of shook my head and said, I can't tell.
O'MARA: So your words were, I can't tell.
MARTIN: Something to that effect, but I never said, no, that that wasn't my son's voice.
ALLEN: Later, Tracy Martin says he listened to the recording 20 times in a row and concluded it was his son calling for help.
Zimmerman's defense says they expect to present just two more days of witnesses. If so, the jury may receive the case and begin deliberations by the end of the week.
Greg Allen, NPR news, Miami. Transcript provided by NPR, Copyright NPR.
