Authorities in Florida have released nearly 200 pages of documents and other items from the investigation of the shooting death of an unarmed black teenager by a neighborhood watch volunteer.

The documents released Thursday include the autopsy report on 17-year-old Trayvon Martin, photographs of Trayvon's killer, George Zimmerman, in the hours shortly after the shooting, and video of Martin at a convenience store moments before the fatal shooting on February 26.

The autopsy revealed Martin was shot at close range through the heart, and had traces of marijuana in his system at the time of the shooting. Photos of Zimmerman taken after he was taken into police custody show cuts and bloody gashes across his face and the back of his head. Zimmerman has claimed he shot the teenager in self-defense.

The documents also include a report from an FBI expert who said there was no way to determine if it was Martin or Zimmerman who was screaming for help during an emergency call from a neighbor shortly before the fatal shot was fired.

Another document in the file was a police report that said there was no evidence Martin was involved in any criminal activity, and that the incident could have been avoided if Zimmerman had remained in his vehicle and waited for police to arrive, instead of following the teenager and confronting him.

Zimmerman is charged with second-degree murder in the shooting death of Trayvon Martin. Police initially refused to charge Zimmerman under Florida's “stand your ground' law, which allows people to use a gun in self-defense if they feel at risk of serious injury or death. The case sparked angry protests across the nation, with demonstrators accusing Zimmerman of racially profiling the boy, as well as anger over the “stand your ground” law.