By Selena Hill (staff@latinospost.com) | First Posted: Jul 04, 2013 09:31 PM EDT

On Wednesday, a Florida Department of Law Enforcement DNA analyst testified that the DNA of slain Florida teen Trayvon Martin was not detected on George Zimmerman's gun.

Zimmerman, 29, who is half white and Hispanic, is facing life in prison for second-degree murder after he fatally shot the unarmed 17-year-old in central Florida back in February 2012. Zimmerman has pleaded not guilty, arguing that he acted in self-defense after he got into a confrontation with the African American teenager.  As part of his defense, Zimmerman claims that Martin reached for his firearm during their scuffle which prompted him to shoot Martin in order to save his own life.

However, the DNA expert, Anthony Gorgone, testified that Zimmerman's DNA wasn't found under the Martin's fingernails either, reports CBS News.

Gorgone added that he didn't detect any DNA that wasn't Martin's on the cuffs and sleeves on the hoodie that he was wearing on the night that he was killed.

During his cross-examination, Gorgone admitted that it was possible to touch something without leaving DNA evidence.

"Sometimes you can touch an item and there won't be any DNA," said defense attorney Don West. "Sometimes there can also be blood, but it can be wiped off."

"That's correct," Gorgone replied.

It remains to be seen whether or not prosecutors will call one or both of Martin's parents to the witness stand to testify about whose voice is on 911 recordings of a fight between Zimmerman and Martin that preceded the shooting, notes Fox News.

Zimmerman's attorneys claim that he is the one screaming on the recordings, while Martin's parents have said it's their son. The screams are crucial pieces of evidence because they could determine who the aggressor was in the confrontation. An FBI expert testified earlier in the week that a person familiar with a voice is in the best position to identify it.

Court re-convene on Friday. Prosecutor Bernie de la Rionda said in court Wednesday that the state will rest their case by "Friday morning at the latest."