SANFORD, Fla. - Prosecutors wrapped their case against GeorgeZimmerman on Friday afternoon after the mother and brother of teenagerTrayvon Martin testified Friday that they believed the screams on a 911call seconds before his death were his, not those of Zimmerman.

"Iheard my son screaming," said Sybrina Fulton, who listened to the 911tape of the final moments of his life on Feb. 26, 2012. Fulton said shehad to listen to the tape only once to know it was her 17-year-old son.She also testified that she didn't think Trayvon was responsible for hisown death.

The defense began with Zimmerman's mother, GladysZimmerman, briefly testifying that it was her son screaming for help onthe phone. "That's George's voice,'' she said.

Friday, O'Marasaid he was pleased with Friday's developments. "I'm happy with the wayit worked out," he said. "They (the jury) will look at both and saythat's certainly what that mom hopes happened."

Gladys Zimmerman'stestimony came after medical examiner Shiping Bao, who autopsiedTrayvon's body a day after his death, said Trayvon died from a 9mmgunshot wound to the heart. "My belief he was still alive, he was stillin pain, he was still suffering'' in the moments after he was shot.

Healso said he believed that based on his experience Travyon was alivefor between one and 10 minutes after he was shot by the weapon, whichhad "loose contact" with his body.

After Bao's testimony,Zimmerman defense attorney Mark O'Mara attempted to have the case thrownout for lack of evidence and his client acquitted. "There's enormousevidence that my client acted in self-defense,'' O'Mara said. "There isno other reasonable hypothesis."

O'Mara said prosecutors failedto prove that Zimmerman acted in ill will, spite or hatred, which isneeded to convict someone of second-degree murder. "I would suggestthere's no direct evidence to support second-degree murder," O'Marasaid, adding that the state failed to provide enough circumstantialevidence to prove their case. He referenced multiple conflictingwitnesses that by themselves, he said, created reasonable doubt.

Judge Debra Nelson denied the acquittal bid.

O'Maraexpects his case will last a few days and that he may re-call somestate witnesses to testify. Meanwhile, O'Mara said, he will spend theweekend doing depositions and planning his strategy for Monday morning.

Sofar, his case has included two witnesses, both relatives of his client."I wanted to get out the reality that everyone in the Zimmerman familyknows that was George Zimmerman screaming," O'Mara said.

EarlierFriday, several autopsy photos were shown of Trayvon's body including aclose-up of his left hand, which had a cut with blood still visible. Thejury stared at the photos that showed Trayvon's clenched hands, a bentleg and a close-up of his face, his eyes and lips closed. The teen'smother was not in the courtroom when the photos were shown but Trayvon'sfather sat somberly looking at the pictures.

Bao said abrasionson two of Trayvon's fingers could have been caused before, after orduring the struggle with Zimmerman, and could have come from punchingsomeone, scraping against concrete or from falling after he was shot.

Thatinformation means Zimmerman's versions of events - that Trayvon punchedhim and banged Zimmerman's head into a concrete sidewalk - could besupported by the teen's autopsy.

O'Mara pressed Sybrina Fultonabout when she heard the tape and whether she hoped the voice was herson's so she would know the teen hadn't caused his own death. "I didn'thope for anything," Fulton said. "I simply listened to the tape."

Trayvon'solder brother, Jahvaris, a 22-year-old senior at Florida InternationalUniversity, also testified that after listening to the 911 tape 10 to15 times, he also believed the screams were made by his brother.

GeorgeZimmerman's uncle, Jorge Meza, also testified that the voice screamingbelonged to George Zimmerman. Meza said he heard the 911 call through atelevision in his home. At the time, Meza didn't know the 911 call wasconnected to his nephew but as soon as he heard it, he knew it wasGeorge Zimmerman, Meza said.

"It was George Zimmerman screaming for his life," Meza said. "I felt it inside of my heart that it is George."

Thefamily members' testimonies could be key to help jurors determine whowas the aggressor in the case against Zimmerman, 29, on trial forsecond-degree murder for Trayvon's death. Zimmerman, the neighborhoodwatch volunteer who has pleaded not guilty, has said that he acted inself-defense after he was attacked.

State attorneys, who havecalled three dozen witnesses, have presented a theory that points toZimmerman's motivation: frustrated by neighborhood burglaries, hewrongly profiled an innocent 17-year-old as a criminal, followed him,then shot and killed him after a struggle.

Despite theprosecution's efforts, several legal experts say the case againstZimmerman isn't strong and does not overcome the burden of reasonabledoubt.

"There are significant weaknesses in the state's case -most importantly conflicting eyewitness accounts which themselves createreasonable doubt as to what happened that night," said ElizabethParker, a former prosecutor who is now a criminal defense attorney inPalm Beach, Fla.

Trayvon's death and the speculation thatZimmerman, who is Hispanic, profiled, followed and murdered him sparkedprotests around the country last year. Zimmerman, who faces life inprison if convicted, has maintained that race did not factor into hisactions.

Benjamin Crump, the attorney for Trayvon's family, hasmaintained that prosecutors have enough to convict Zimmerman. "There isoverwhelming evidence that George Zimmerman murdered Trayvon Martin," hehas said.

Eyewitness accounts concern Parker however,particularly the testimony from residents who lived nearby the shootingscene who told largely different stories.

Jonathan Good said he saw Trayvon on top of and striking Zimmerman moments before the teen was shot.

SelmaMora, who lived a couple of houses down from Good, said a personstraddling on top of another person told her to call police. Minuteslater, the same person who was on top, Zimmerman, was on his feet after agunshot, Mora said.

Meanwhile, two key witnesses, Sanford PoliceOfficer Christopher Serino, the lead investigator on the case, andRachel Jeantel, a young woman who was on the phone with Trayvon momentsbefore he died, did not significantly help the state, Parker said.

Serino agreed with prosecutors that Zimmerman may have been profilingTrayvon, who was black, but also said he believed Zimmerman was tellingthe truth when he said he was attacked by the teen he fatally shot. Thejudge later told the jury to disregard that Serino believed Zimmerman.

"Serino'stestimony was frankly terrible for the state," said Randy Reep, aJacksonville defense attorney. "The instruction from the judge to ignorehis views of Zimmerman's honesty was the correct thing for the judge todo, but un-ringing that bell is impossible to do."

Theinvestigator also told the jury no physical evidence or witnessstatements contradicted Zimmerman's claim of self-defense and that themedical examiner's report supported Zimmerman's version of events.

Meanwhile,Jeantel, 19, told jurors that Zimmerman stared at and then followedTrayvon who tried several times to run away. Trayvon was out of breathwhen he told Jeantel he had lost the man.

"It was kind of strange that a person kept watching and following," she said. "It was like being stalked."

Later,Trayvon told Jeantel the man was back and behind him, she said. Withinseconds, she said she heard a "bump" and Trayvon saying "get off." Thephone hung up and there was no answer when she called back.

However,Jeantel and defense attorney Don West sparred during a seven-hourcross-examination that was often contentious. Jeantel admitted duringtestimony that she had lied twice: She said she told Trayvon's familyshe was 16 when she was 18. She also said she lied about going to ahospital instead of Trayvon's funeral because she didn't want to see hisbody.

Jeantel also said when she was first interviewed by a stateattorney, it was at Trayvon's mother's house. Sybrina Fulton, Trayvon'smother, was crying and Jeantel didn't want to upset her further, theteen said.

"Rachel Jeantel's testimony was crucial to the state's case," Parker said. "She was Trayvon's voice from the grave."

ButParker thought the high school senior came across as aggressive andhostile and that her version of the truth seemed to lack credibility.

Thethree most troubling issues with Jeantel were that her accountsregarding what she heard were not consistent, her testimony appeared tobe inappropriately influenced by the state, and she didn't appear totake testifying seriously, Parker said.

Daryl Parks, anotherattorney for the family of Trayvon, said his clients were proud ofJeantel and that the teen stuck to what she heard, that Zimmerman wasthe aggressor.

"She is not a lawyer," Parks said. "She did her very best."

Otherstate witnesses testified that Trayvon's fingerprints and DNA were notfound on the gun but his DNA was found on the right cuff of Zimmerman'sjacket. They also said Zimmerman's DNA was not found under Trayvon'sfingernails but it was found on a shirt Trayvon wore under his hoodie.

Thejury also learned about Zimmerman's rejection letter from a Virginiapolice department, his course work for a class that discussedstand-your-ground and self-defense laws, and his application to do apolice ride-along.

However, legal experts say prosecutors have notproven Zimmerman acted "imminently dangerous" and demonstrated a"depraved mind without regard for human life" - Florida's definition ofsecond-degree murder.

"What they seem to have proved, instead, is athoughtless, careless encounter that may have spiraled out of control,"said Jules Epstein, a Widener University law professor, adding that theprosecution seemed to take an extreme view of the events.

Contributing: Gary Strauss