Associate medical examiner Shiping Bao MD testifies during the trial.

Reuters/Sanford, Florida

Trayvon Martin’s mother said in court yesterday that she recognised the voice of her son screaming for help in an emergency call on the night the unarmed black Florida teenager was shot dead by neighbourhood watchman George Zimmerman.

Sybrina Fulton’s testimony came as the state was preparing to wrap up its murder case against Zimmerman after nearly two weeks of testimony.

The prosecution has sought to expose inconsistencies in his account of the fight in Sanford, Florida, in February last year that ended with Martin’s death.

Fulton told jurors she was certain it was her son who can be heard screaming for help in the background of an emergency call made to police moments before he died.

“I heard my son screaming,” said Fulton, who added that she first heard the recording in the office of the mayor of this town near Orlando where her son died.

Testimony from voice-recognition experts has been ruled inadmissible in the trial on the grounds that it was impossible to tell from the brief, poor-quality recording whether it was Martin or Zimmerman calling for help.

In addition to Martin’s mother, the state’s final witnesses included his brother, 22-year-old Jahvaris Fulton, who said he too was convinced it was his brother who can be heard screaming on the recording.

Other witnesses yesterday, as the state ran through the last of dozens of people it has called to testify, included the central Florida medical examiner who performed the autopsy on Martin.

Dr Shiping Bao said Martin did not die instantly, even though the lone bullet from Zimmerman’s 9mm Kel-Tec semi-automatic handgun pierced the right ventricle of his heart.

“It is my opinion that he was still alive, he was still in pain, he was still suffering,” said Bao, even as he stressed that the wound was something Martin could not possibly have survived.

“I believe that he was alive for one to 10 minutes after he was shot,” he added.

Bao’s testimony was accompanied by graphic photographs from the autopsy that were shown to jurors. He did not explain how Martin could have been in pain, if he lost consciousness before he died, and acknowledged that he previously said the youth may only have lived for up to three minutes after the shooting.

Once the prosecution rests its so-called “case in chief”, it will be the turn of the defence to present its case.

Legal experts said that before doing so, Zimmerman’s legal team could simply make an argument for acquittal on grounds that the state has failed to meet its burden of proof.

It is still unclear whether the defence will choose to put Zimmerman, who is 29 and part Hispanic, on the stand to testify.

The former neighbourhood watchman contends that he killed Martin in self-defence. He faces up to life in prison if convicted of second-degree murder.

After the defence concludes its case, the prosecution is entitled to present a rebuttal.