By Selena Hill (staff@latinospost.com) | First Posted: Jul 09, 2013 05:07 PM EDT

According to a nationally renowned gunshot wound expert, Trayvon Martin was leaning over George Zimmerman when the neighborhood watch volunteer fired the fatal shot into the unarmed teenager's body.

Dr. Vincent Di Maio delivered this testimony on Tuesday during the 11th day of the George Zimmerman second-degree murder case, providing evidence that the gunshot wound was consistent with Zimmerman's story that the teen was on top of him when he was shot, reports CBS News.

Zimmerman, 29, 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.

The forensic pathologist said that he had examined the autopsy, toxicology and photographic evidence and concluded that the evidence was consistent with Zimmerman's statements to authorities that Martin was straddling him and that he fired his gun with his right hand. The bullet entered Martin's body on the left side through part of his heart, and ran into a portion of the right lung, Di Maio testified, reports the LA Times.

Di Maio said he based his conclusions on analysis of debris from the gunshot, including the "powder tattoo marks" surrounding the wound, which give the appearance of a reddish, circular rash on the skin. He said those marks would not be present if the muzzle had been held against Martin's skin.

"So ... the muzzle of the gun was against the clothing. But the clothing itself had to be two to four inches away from the body at the time Mr. Martin was shot," he said.

"This is consistent with Mr. Zimmerman's account - that Mr. Martin was over him, leaning forward at the time he was shot," Di Maio said.

Di Maio added that there was "definite evidence" of six impacts that caused wounds to Zimmerman's nose, the back of his head and his forehead. Those injuries were also consistent with Zimmerman's account of events that Martin slammed his head into the ground multiple times, Di Maio said.