Defendant in Trayvon Martin shooting case makes defence gamble ahead of June trial on second-degree murder charges

George Zimmerman told a judge on Tuesday that he "freely and voluntarily" waived his right to seek immunity from prosecution for the murder of Trayvon Martin under Florida's controversial stand-your-ground law.

The decision marked a point of no return for the former neighbourhood watch leader, who must now face a trial in June for the second-degree murder of the teenager he shot during a confrontation at a Florida housing estate in February 2012.

Zimmerman, 29, could still invoke at trial the stand-your-ground law, which allows for the use of deadly force when a person fears their life is in danger. But the gamble places his fate in the hands of a jury and exposes to him a prison term of at least 25 years if he is convicted, instead of allowing circuit court judge Debra Nelson to rule at a separate immunity hearing and possibly dismiss the charge.

Nelson questioned Zimmerman directly at Tuesday's hearing in Sanford, at which he confirmed he consented to his lawyers abandoning the strategy that they had cited repeatedly since his arrest last year. "Has anybody promised you anything to get you to make this decision? Has anybody threatened you?" Nelson asked.

"No, your honour," Zimmerman replied.

"Is your decision freely and voluntarily and knowingly made?" Nelson continued.

"Yes, your honour," Zimmerman said.

Earlier in the hearing, which involved numerous testy exchanges between prosecution and defence lawyers over a number of separate pre-trial motions, Zimmerman's attorney, Mark O'Mara, clarified his thinking for not asking Nelson for the immunity hearing. "Why go to a trial if you can address and resolve the issue ahead of time?" he said.

"Because, as I've mentioned at a previous hearing, because of the unique nature of this case and because of the way we've decided to handle it, we would much rather have a jury address the issue of criminal liability or lack thereof. There's nothing in the rules that suggests that has to be handled pre-trial."

O'Mara announced last month that he intended to take the case straight to trial but reserved the right to still seek an immunity hearing. That possibility was removed when a filing deadline passed on Friday.

Zimmerman killed Martin, 17, with a single gunshot to the chest as the pair tussled on the ground during their encounter at the Retreat at Twin Lakes community in Sanford on the night of 26 February last year.

O'Mara insists that his client was acting in self-defence when he shot the teenager, who he claims broke Zimmerman's nose and was repeatedly smashing the older man's head on a concrete pavement.

Prosecutor Bernie de la Rionda, however, said Zimmerman was the aggressor, profiling the black teenager and pursuing and confronting him after being told not to by a police dispatcher. Martin, from Miami, was walking back to a house owned by his father's friend carrying candy and a soft drink he had bought at a nearby shop.

The initial decision by Sanford police to release Zimmerman without charge sparked racial tensions and put Florida's gun laws under the spotlight. Sanford's police chief eventually lost his job and Florida governor Rick Scott handed the case to a special prosecutor, who filed the murder charge more than six weeks after Martin's death.

The angry exchanges at Tuesday's hearing followed a recent pattern of animosity between the defence and prosecution, with both sides blaming the other of withholding key evidence. "They're not giving us information," O'Mara told Judge Nelson, accusing the state of "deceit".

"We will be unprepared for trial because of everything they've done to us, unless you tell them to stop doing it and to play by the rules they are supposed to play by," he said.

De la Rionda, meanwhile, has previously criticised O'Mara for "grandstanding" and courting "anything resembling a camera or microphone".

Nelson rebuked both sides firmly for their recent trading of insults, reminding them that she had sent them both copies of professional conduct guidelines.

One of the motions on Tuesday involved the existence of a "cleaned-up" version of the recording of a 911 call that captured somebody screaming just before the fatal shot. Defence lawyer Don West said the dead boy's father, Tracy Martin, was played a digitally enhanced version of the call from at which he identified his son's voice, and he demanded that it be released by the prosecution.

De la Rionda, however, said such a copy did not exist because the recording was still with experts.

West also claimed that the prosecution possessed data recovered from Martin's cellphone that it had not declared, something de la Rionda also denied. Nelson ruled that the enhanced tape, and any new information obtained from the phone, must be released to the defence within 24 hours of receipt by the prosecution.

She also ordered the release of a redacted copy of a wrongful death settlement earlier this month between the Retreat at Twin Lakes homeowners association and Martin's parents. O'Mara wanted the settlement fully disclosed, but Nelson's ruling will conceal the financial details.

Two other motions from O'Mara seeking financial compensation from the state for time he says he wasted on the case through prosecutorial delays were deferred to a post-trial hearing.

© Guardian News and Media 2013