SANFORD, Florida (AFP) - The father of a black teenager shot dead by a neighborhood watch volunteer walked out of a Florida court on Tuesday as photos of his son's body were shown.
During a dramatic second day in the racially-charged trial, Tracy Martin left the courtroom as a close-up image was shown highlighting the bullet wound suffered by his son Trayvon.
The 17-year-old was shot dead by defendant George Zimmerman during an altercation at a gated community last February.
Police sergeant Anthony Raimondo told the court he had tried to revive Martin after arriving at the scene of the killing soon after the shooting.
"I attempted to get his pulse," said Raimondo. "I also performed CPR. I breathed for Mr Martin...I tried to, sir." Prosecutors say Zimmerman, 29, committed second degree murder when he shot Martin dead.
Zimmerman has pleaded not guilty, denies he was suspicious of Martin because of his race and says he shot in self-defence after the teenager wrestled him to the ground and pounded his head against the sidewalk.
Earlier Tuesday, prosecutors said Zimmerman had made nearly 50 calls to police in the years leading up to the killing and argued for these conversations with police dispatchers to be admitted as evidence.
Prosecutors say the tapes reveal a pattern of over-zealous behaviour by Zimmerman prior to the killing, while defence attorneys argued for the recordings to be excluded under the rules of evidence.
The court heard that Zimmerman called police dozens of times in eight years to report issues such as slow vehicles, strangers in the neighbourhood and open garages.
But defence attorney Mark O'Mara said Zimmerman's past actions were irrelevant and that only the moments immediately before Martin's killing should be in the spotlight.
"They're going to ask the jury to make a leap from a good, responsible, citizen behaviour to seething behaviour," Mr O'Mara argued before Judge Debra Nelson.
Judge Debra Nelson said she would make a ruling on the admissibility of the tapes after reviewing prior cases. The lawyers made their arguments with the jury out of the courtroom.
In other testimony on Tuesday, the president of the homeowners association at the gated community where the killing took place told the court Zimmerman had pushed for the neighborhood watch program despite his misgivings.
"I didn't think we needed it," said Donald O'Brien, president of the Retreat at Twin Lakes Homeowners Association.
Mr O'Brien said volunteers at a neighborhood watch presentation had also been told to call police if they saw anything suspicious.
"We were told to stay away from suspicious people and call police," he said.
Ms Wendy Dorival, a former co-ordinator of the Sanford Police Department's neighbourhood watch programme, said she had helped Zimmerman set up the programme.
She revealed that Zimmerman and all neighbourhood watch participants were warned not to follow suspicious people.
"They're told 'don't do that. That's the job of law enforcement,'" she said. "Volunteers are encouraged to keep an eye out for suspicious people and report them, but not to take matters into their own hands."
Zimmerman, a volunteer night watchman whose father is white and whose mother is Peruvian, reported Martin to police in a 911 call in which the dispatcher told him not to follow the teenager.
Police in the central Florida city of Sanford initially released Zimmerman, saying he acted in line with Florida's "stand your ground" laws, which allow citizens to defend themselves with deadly force.
But Zimmerman was later arrested and faces life in prison if convicted.