Yet another witness described the confrontation in emotional terms.
The witness heard "someone yelling, almost crying. Then I heard a gunshot." The witness wrote that he or she "saw a man on top of a guy laying on the ground. He was putting his hands on his neck or chest."
The man asked the witness to call 911.
"He stood up and took a couple steps away and put his hands on his head and then walked back over to the guy on the ground. He looked at him for a minute, then started to walk away toward the road. That is when the police walked up," the witness wrote.
The lead investigator on the case, Officer Christopher Serino, wrote that Zimmerman could be heard "yelling for help as he was being battered by Trayvon Martin."
Martin's death sparked public outrage after police released Zimmerman without any criminal charges for the killing. Zimmerman was later charged with second-degree murder, and the killing provoked widespread debate about racial profiling.
The autopsy also shows that Zimmerman shot Martin from a distance of between 1 inch and 18 inches away, bolstering Zimmerman's claim that he shot Martin during a close struggle.
Martin's autopsy report also revealed that there was a quarter-inch by half-inch abrasion on the left fourth finger of Martin, another indication of a possible struggle.
The teen, who lived in Miami, was in Sanford while serving a suspension for an empty marijuana bag discovered in his possession. Martin had THC, the drug found in marijuana, in his blood on the night of his death, according to the autopsy. His family told ABC News that it was "trace amounts" of THC.