A leaked autopsy reportedly shows that the bullet that killed Florida teen Trayvon Martin was fired from "intermediate range," which one forensics expert said means anywhere from one to 18 inches away.

The autopsy, conducted by the medical examiner in Volusia County, Fla., also showed that 17-year-old Martin had one small abrasion on his left ring finger below the knuckle, according to the news report. The report could back the account of George Zimmerman, the 28-year-old neighborhood watch captain accused of killing Martin, who has said he fired into Martin's chest in self-defense as the youth was straddling and pummeling him.

The autopsy report was reviewed by NBC News, but not made available to the public. A spokesman for Volusia County, Fla., told Fox News the report was not made public and was leaked by someone other than the Volusia County Medical Examiner's Office. He noted attorneys for both Zimmerman and Martin had copies of it. He said the report will not be released while an active investigation of the Feb. 26 shooting remains underway.

Dr. Michael Baden, the former New York City medical examiner, said "intermediate" in such cases is defined as the muzzle of the gun being one to 18 inches away from the entry point when fired. 

"If the muzzle is right against the skin, that's a contact wound," Baden said. Anything beyond 18 inches is considered "distant" range in coroner's parlance, Baden said.

The autopsy results surface as court records indicate that Zimmerman sustained multiple injuries. Zimmerman, who is claiming self-defense in the fatal shooting on Feb. 26, had a pair of black eyes, a fractured nose and two cuts to the back of his head, according to a medical report prepared by his personal physician.

Some legal experts say the report on Zimmerman's injuries, first reviewed by ABC News, may bolster his claim that he shot Martin in self-defense.

Zimmerman, a 28-year-old Neighborhood Watch volunteer, has pleaded not guilty to a second-degree murder charge in the shooting of Martin outside a gated community in Sanford, Fla. Zimmerman, who is free on $150,000 bail and is living in an undisclosed location, claims he only fired his handgun because Martin attacked him.

The case has become a national racial flashpoint because the Martin family and supporters contend Zimmerman singled Martin out because he was black. It has also sparked renewed debate over "stand your ground" laws pushed by the National Rifle Association.

The police investigation into Martin's death also has been roundly criticized by his family and others. The New York Times reported Wednesday that the police investigation into the fatal shooting was riddled with missteps from the beginning, making it a difficult case to pursue. Police reportedly took only one cellphone photo at the scene of Zimmerman's injuries, and they did not test him for any alcohol or drug use that night. Local authorities were also unable to protect potential evidence at the scene -- like blood -- from getting washed away by the rain, according to the newspaper.

The Associated Press contributed to this report.