SANFORD, Fla. -

On the night Trayvon Martin died at The Retreat at Twin Lakes in Sanford, John Good said he was nearby sitting on the couch. 

Prosecutor Bernie de la Rionda and defense attorney Mark O'Mara asked Good to describe what he saw Feb. 26, 2012 during testimony in the George Zimmerman trial Friday morning. His account contradicted that of witness Selma Mora, who said Thursday Zimmerman was on top of Trayvon before he fired the gun.

Good remembers he was watching T.V. when he heard some noise outside. He muted the T.V.  It was raining.

"It seemed like it [the noise] was getting closer," he said.

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Good stood up and peeked through the vertical blinds. He couldn't really see anything. He opened the sliding door and  took one step outside the door.

"There was arm motion going downward," he said.

Good said it was dark outside, and he could only see there were two people on the ground. The person on the bottom had a lighter skin tone, he said. But he is not sure if it was Trayvon or Zimmerman.

Good said he yelled out "'What's going on?' and 'Stop it!"

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He heard a person crying for help, but could not identify who it was. Good shouted: "CUT IT OUT!" No one answered.

That's when "they moved over to the cement," he said.

Good said he saw one man on top of the other in an mixed-martial arts style "straddle position." He did not see anyone smashing anyone's head to the ground, as Zimmerman claims.

Good rushed back inside to call the police. And then he heard a gunshot. De la Rionda  and O'Mara played a recording of Good's emergency call.

"They guy is yelling help ... I'm pretty sure a guy is dead out here," he told the 911 operator.