Zimmerman, so far, hasn't testified. But jurors saw repeated video recordings of Zimmerman telling his side of the story to police investigators.
The defence started its case last Friday. If it keeps to the schedule anticipated by defence attorney Mark O'Mara, its presentation will take about half of the time of the prosecution and call on about half as many witnesses.
Judge Debra Nelson still has to decide on two requests by the defence:- Whether to allow jurors to view an animation that depicts Zimmerman's fight with Martin, who was killed in a gated community in Sanford, Fla., last year.
- Whether she will allow Martin's text messages that purportedly deal with fighting.
The judge said she would rule on both matters Wednesday.
Martin was unarmed and returning from a store when he was fatally shot by Zimmerman on a dark, rainy night in February 2012. Martin was black and Zimmerman identifies himself as Hispanic. Some civil rights activists argued that the initial delay in charging Zimmerman was influenced by Martin's race.
Prosecutors oppose defence requests
Prosecutors opposed the introduction of the animation, which shows Zimmerman's version of the confrontation, saying it was inaccurate and would confuse jurors. Prosecutors also don't want jurors to learn about the texts, claiming they are misleading and prejudicial.
Defence attorney Don West argued late Tuesday that the texts were relevant because "it relates to his physical capabilities, his knowledge of fighting."
As an evidence hearing with jurors out of the courtroom dragged past 10 p.m. Tuesday, West complained that the defence hadn't been given Martin's cellphone data by prosecutors in a timely manner, which would have allowed them to authenticate the messages.
"It's simply unfair for Mr. Zimmerman not to be able to put on his defence because of these tactics," West said.
When a frustrated Nelson abruptly told the attorneys that she would rule Wednesday, West continued to address her after she had officially adjourned court for the evening. He complained about a schedule that had lawyers working weekends and taking multiple depositions during the trial, for which jurors have been sequestered.
Prosecutor John Guy said jurors shouldn't be presented with the text messages and photos of a gun found on Martin's phone, as well as a Facebook posting from a half-brother asking Martin when he was going to teach him how to fight.
Pathologist testifies for defence
Jurors spent a significant part of Tuesday listening to a defence expert on gunshot wounds testify that the trajectory of the bullet and gunpowder on Martin's body support Zimmerman's account that the teenager was on top of the defendant when he shot and killed Martin.
Dr. Vincent DiMaio, the forensic pathologist, also used photographs of Zimmerman to point out where he appeared to have been struck. Defence attorneys were hoping DiMaio's testimony would help convince jurors of Zimmerman's claims that he shot Martin in self-defence.
DiMaio said the muzzle of Zimmerman's gun was against Martin's clothing and it was anywhere from five to 10 centimetres from Martin's skin.
"This is consistent with Mr. Zimmerman's account that Mr. Martin was over him, leaning forward at the time he was shot," said DiMaio, the former chief medical examiner in San Antonio.
DiMaio testified that lacerations to the back of Zimmerman's head were consistent with it striking a concrete sidewalk, as the defendant has claimed. Later, when looking at photos of Zimmerman's injuries taken the night of the shooting, DiMaio identified six separate impacts to Zimmerman's face and head. He said he believed Zimmerman's nose had been broken.
"It's obvious he's been punched in the nose and hit in the head," he said.
Under cross-examination, DiMaio conceded that the gunshot could also be consistent with Martin pulling away from Zimmerman, and that he reached his conclusion without factoring in statements from some neighbors who say Zimmerman was on top of Martin. DiMaio, who has testified at high-profile trials including that of record producer Phil Spector, said witness accounts are often unreliable. The pathologist said he had been paid $2,400 US by the defence.
911 calls discussed again
DiMaio's testimony also addressed the difference between Zimmerman's account that he had placed Martin's arms out to his sides and a photo taken after the shooting that shows Martin's arms under his body. The pathologist said Martin would have been conscious for 10 to 15 seconds after the shooting as a reserve supply of oxygen ran out of his body, and during that time he could have moved his arms.
After DiMaio testified, the 911 calls that captured sounds of the fatal encounter were discussed again. Defence attorneys called Sanford city manager Norton Bonaparte to the witness stand to describe the circumstances of how Martin's family came to hear the 911 tapes. Bonaparte said he played the 911 tapes while members of Martin's family sat together at City Hall. He played them as a courtesy before they were released publicly.
Defence attorneys are trying to show that Martin's family members may have influenced each other in concluding the screams are those of the Miami teen. Police officers testified for the defense that it's better for someone who is trying to identify a voice to listen to it alone.
Convincing the jury of who was screaming for help on the tape has become the primary goal of prosecutors and defence attorneys because it would help jurors evaluate Zimmerman's self-defence claim. Relatives of Martin's and Zimmerman's have offered conflicting opinions about who is heard screaming.
Zimmerman has pleaded not guilty to second-degree murder and says he shot Martin in self-defence during a scuffle in the townhome complex where he lived. Martin was there visiting his father and his father's fiancée.