SANFORD, Fla. -

Two neighbors and a police officer gave accounts Friday in George Zimmerman's murder trial that seemed to bolster the neighborhood watch volunteer's contention that he was on his back and being straddled by Trayvon Martin during a confrontation with the teen.

Neighbor Jonathan Good said it appeared the unarmed teen was straddling Zimmerman during their confrontation, while another neighbor, Jonathan Manalo, said Zimmerman seemed credible when he said immediately after the fight that he had shot Martin in self-defense. Officer Tim Smith said on the witness stand that Zimmerman's backside was covered in grass and wetter than his front side.

All three were called as prosecution witnesses on the fifth day of testimony.

Good, who had perhaps the best view of the fight of any witness, said he did not see anyone's head being slammed into the concrete sidewalk, which Zimmerman has said Martin did to him. Good initially testified that it appeared "there were strikes being thrown, punches being thrown," but during detailed questioning he said he saw only "downward" arm movements being made.

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Zimmerman has claimed that he fatally shot 17-year-old Martin last year in self-defense as the Miami-area teen was banging his head into the concrete sidewalk behind the townhomes in a gated community.

But under prosecution questioning, Jonathan Good said he never saw anyone being attacked that way during the fight between Zimmerman and Martin.

"I couldn't see that," Good said moments later while being cross-examined.

Good, the second person to take the witness stand Friday, said he heard a noise behind his townhome in February 2012, and he saw what looked like a tussle when he stepped out onto his patio to see what was happening.

He said he yelled, "What's going on? Stop it."

Good testified he saw a person in black clothing on top of another person with "white or red" clothing. He said he couldn't see faces but it looked like the person on the bottom had lighter skin. Martin was black and was wearing a dark hoodie. Zimmerman identifies as Hispanic and was wearing a red jacket.

"It looked like there were strikes being thrown, punches being thrown," Good said.

Trayvon Martin Later, under cross-examination, he said that it looked like the person on top was straddling the person on bottom in a mixed-martial arts move known as "ground and pound." When defense attorney Mark O'Mara asked him if the person on top was Martin, Good said, "Correct, that's what it looked like."

Good also said the person on the bottom yelled for help.

Good was in the middle of dialing 911 inside his townhome when he heard a gunshot, he said.

Zimmerman, 29, could get life in prison if convicted of second-degree murder. Zimmerman followed Martin in his truck and called a police dispatch number before he and the teen got into a fight.

Zimmerman has denied the confrontation had anything to do with race, as Martin's family and their supporters have claimed.

Manalo, whose wife had testified earlier in the week, was the first neighbor to step outside and see what happened with his flashlight after he heard a gunshot. He took cellphone photos of a bloodied Zimmerman and Martin's body, and those photos were shown to jurors on Friday. Manalo also described Martin's hands as being under his body.

Manalo said Zimmerman didn't appear shocked and acted calmly. After police officers arrived and handcuffed Zimmerman, the neighborhood watch volunteer asked Manalo to call his wife and tell her what happened.

Manalo started to tell Zimmerman's wife that her husband had been involved in a shooting and was being questioned by police when "he cut me off and said, 'Just tell her I shot someone,'" Manalo said.

Under cross-examination, Manalo said when he asked Zimmerman what happened, the neighborhood watch volunteer told him, "I was defending myself and I shot him."

"From what you could tell at that moment, that seemed completely true?" asked defense attorney Don West.

"Yes," Manalo said.

The first police officer and the first paramedic to respond to the shooting also testified Friday. Smith testified that when he saw Zimmerman after the shooting, the neighborhood watch volunteer's backside was covered in grass and wetter than his front side, bolstering defense attorneys' contention that Martin was on top of Zimmerman.

As he walked to the squad car after he had been handcuffed, Zimmerman told the officer that "he was yelling for help and nobody would come help him," Smith said.

"It was almost a defeated ... a confused look on his face," Smith said.

Smith said Zimmerman described himself as "lightheaded" during the drive to Sanford Police Station but declined an offer to take him to a hospital.

Paramedic Stacy Livingston said Zimmerman had a swollen, bleeding nose and two cuts on the back of his head an inch long. When O'Mara asked if Zimmerman should have been concerned with his medical well-being because of his injuries, Livingston said, "Possibly."

When photos of Martin's body were shown on a courtroom projector during Livingston's testimony, Martin's mother, Sybrina Fulton, looked away and blinked back tears.

Zimmerman trial over teen's death enters 5th day

In testy exchanges, George Zimmerman's defense attorney insinuated that the young woman who was on the phone with Trayvon Martin shortly before he was fatally shot was not believable because of inconsistencies in her story.

But 19-year-old Rachel Jeantel held firm in her testimony about what she heard over the phone while talking with Martin the night the unarmed teen was shot and killed by Zimmerman, a neighborhood watch volunteer.

Testimony in the case was entering its fifth day Friday with jurors having already been exposed to some of the state's biggest pieces of evidence, including the 911 call featuring cries for help prosecutors believe came from Martin, as well as the sound of the gunshot moments later which killed him.

In her testimony, Jeantel contended that it was Zimmerman who confronted Martin. Zimmerman, who claims the shooting was in self-defense, has said he opened fire only after the 17-year-old jumped him and began slamming his head against the concrete sidewalk.

"We're in the middle of it," defense attorney Mark O'Mara said. "They've got a lot more to show. These things build up slow, and it's sort of like pieces of a puzzle. People say, `wait a minute, I can't see the picture yet.' They're very good prosecutors, they're gonna do very good job, and they're gonna put on their evidence. We'll see how it goes. We're certainly ready to respond to it."

Rachel Jeantel During Jeantel's testimony, O'Mara's co-counsel Don West insisted Thursday that Martin injected race into the confrontation. Jeantel has said Martin told her he was being followed by a "creepy-ass cracker" -- implying Martin was being followed by a white man because of his race.

Zimmerman identifies as Hispanic. Race has permeated nationwide discussions of the case since the February 2012 shooting, which prompted nationwide protests and claims from critics that police took too long to arrest Zimmerman.

West also zeroed in on slight differences among three different accounts of what happened before Martin's killing, in an apparent effort to discredit her. Jeantel has described what she heard over the phone in a deposition; a letter to Martin's mother; and an interview with the Martin family attorney. Among the differences highlighted by West:

- In some accounts, she said race was an issue but not in others.

- Jeantel testified Wednesday that her friend's last words were "Get off! Get off!" before Martin's phone went silent. But on Thursday, under cross-examination, she conceded that she hadn't mentioned that in her account of what happened to Martin's mother, Sybrina Fulton. She had left out some details to spare Fulton's feelings, and also because neither Fulton nor the Martin family attorney asked her directly about them, Jeantel said.

- After Martin asks why he is being followed, Zimmerman responds, "What are you doing around here?" in one account by Jeantel. In another account, according to West, she says Zimmerman said, "What are you talking about?"

Zimmerman, 29, could get life in prison if convicted of second-degree murder. Zimmerman followed Martin in his truck and called a police dispatch number before he and the teen got into a fight.

Zimmerman has denied the confrontation had anything to do with race, as Martin's family and their supporters have claimed.

Jeantel testified Thursday that she thought race was an issue because Martin told her he was being followed by a white man.

But West responded, "It was racial because Trayvon put race in this?"

She answered no.

The exchanges got testier as the day progressed.

When asked by West if she had previously told investigators that she heard what sounded like somebody being hit at the end of her call with Martin, Jeantel said, "Trayvon got hit."

"You don't know that? Do you? You don't know that Trayvon got hit," West answered angrily. "You don't know that Trayvon didn't at that moment take his fists and drive them into George Zimmerman's face."

Later in the morning, West accused Jeantel of not calling police after Martin's phone went dead because she thought it was a fight he had provoked.

"That's why you weren't worried. That's why you didn't do anything because Trayvon Martin started the fight, and you knew that," West said.

"No sir!" Jeantel said. "I don't know what you're talking about."

At one point, West handed her a letter she had written with the help of a friend to Martin's mother explaining what happened. She looked at it but then said she couldn't read cursive handwriting. Jeantel later explained she is of Haitian descent and grew up speaking Creole and Spanish.

After Jeantel left the witness stand, a mobile phone manager testified about Martin's cell phone records and a former neighbor of Zimmerman testified she heard yelps for help outside her townhome on the night Martin was shot. Jenna Lauer said she couldn't tell who was screaming.

"They were being hurt," Lauer said, describing the person screaming.

Before court recessed for the day, O'Mara asked another former neighbor to recreate for jurors how she reacted when she heard what turned out to be a gunshot and ran out of her town-house to see what was going on. The request had Selma Mora in the unusual position of standing up from the witness stand and pretending to be in her kitchen in front of the judge's bench.