ORLANDO, Fla. -- Forensic tests made public Wednesday show that George Zimmerman's was the only DNA that could be identified on the grip of the gun used to fatally shoot 17-year-old Trayvon Martin.

The results rule out Martin's DNA from being on the gun's grip. Zimmerman's DNA also was identified on the gun's holster, but no determination could be made as to whether Martin's DNA was on the gun's holster, according to the report from the Florida Department of Law Enforcement.

Zimmerman is charged with second-degree murder for fatally shooting Martin during a confrontation in a gated community in Sanford in February. Zimmerman is pleading not guilty, claiming self-defense.

A delay in Zimmerman's arrest led to nationwide protests.

The question of whose DNA is on the gun and holster could play a role in Zimmerman's defense.

Zimmerman says Martin had been on top of him, slamming his head against the ground and smothering his mouth and nose with his hand and arm when he grabbed his gun from a holster on his waist before Martin could get it. He shot the teenager once in the chest.

Other documents released by prosecutors Wednesday include an interview with the clerk of a convenience store where Martin purchased Skittles and a can of iced tea moments before his confrontation with Zimmerman. The clerk said in the interview, more than a month after Martin was shot, that he didn't remember Martin.

"To be honest, I don't even remember that day," said the clerk, whose name was redacted from the audio interview.

Prosecutors also released hundreds of emails sent to then-Sanford Police Chief Bill Lee whose agency came under fire when Zimmerman wasn't immediately arrested. An email dated more than a week after Martin's death from a resident of the development where Zimmerman was the neighborhood watch leader thanked Lee for attending a recent association meeting. The email's author, Molly Jackson, said in an interview Wednesday that Zimmerman wasn't present at that association meeting.

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Associated Press writers Kyle Hightower in Orlando and Terry Spencer in Miami contributed to this report.

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  • A photograph of George Zimmerman taken the night he shot and killed Trayvon Martin in Sanford, FL.

  • The gun George Zimmerman used to shoot Trayvon Martin can be seen in this evidence photo.

  • George Zimmerman's gun and clip can be seen in this evidence photograph taken by Sanford police. Zimmerman shot and killed Martin after an altercation with the unarmed teen, who was returning to the house where his father was staying on February 26 after a trip to a nearby 7-Eleven.

  • George Zimmerman photographed by police the night he shot and killed Trayvon Martin in a gated community in Sanford, FL.

  • Cuts can be seen on the face of George Zimmerman in this photo taken by police on the night he shot and killed Trayvon Martin. Zimmerman claims that Martin attacked him and banged his head repeatedly on the ground, prompting Zimmerman to shoot the teenager in self-defense.

  • Cuts can be seen on the face of George Zimmerman in this photograph taken the night he shot and killed Trayvon Martin. Zimmerman says he shot Martin during an altercation in which Martin slammed his head repeatedly into the ground.

  • George Zimmerman, photographed by police on the night he shot Trayvon Martin in Sanford, FL.

  • Blood can be seen on the head of George Zimmerman in this police photo taken the night he shot and killed Trayvon Martin. Zimmerman claims he shot Martin, an unarmed teenager, in self-defense.

  • Blood can be seen on the head of George Zimmerman in this police photo taken the night he shot and killed Trayvon Martin.

  • Blood and bruises can be seen on the head of George Zimmerman in this police photo taken the night he shot and killed Trayvon Martin.

  • In this Feb. 27, 2012 image taken from a Sanford Police video posted on a website called gzlegalcase.com by George Zimmerman'sdefense team, Zimmerman speaks to investigators, (not shown) at the scene of Trayvon Martin's fatal shooting a day later giving police a blow-by-blow account of his fight with the teen. On the tape, Zimmerman did a reenactment of the scuffle with Martin in the moments before he shot the 17-year-old from Miami. (AP Photo/Sanford Police video via Zimmerman Defense Team)

  • This photo released by the Seminole County Sheriff's Office shows Shellie Zimmerman. Zimmerman, the wife of the Trayvon Martin shooter George Zimmerman, was charged with perjury and accused of lying when she told a judge that the couple had limited funds during a hearing that resulted in her husband being released on $150,000 bond. She was released on $1,000 bond. (AP Photo/Seminole County Sheriff's Office)