SANFORD, Fla. - A DNA expert said Wednesday tests of George Zimmerman's gun revealed the neighborhood watch volunteer's DNA on the firearm's grip -- but not Trayvon Martin's.
Florida Department of Law Enforcement DNA expert Anthony Gorgone testified that none of Zimmerman's DNA was found underneath Martin's fingernails.
Prosecutors called the DNA expert to the witness stand to refute Zimmerman's contention that he fatally shot Martin in self-defense. Zimmerman has said Martin was reaching for his firearm during a fight when he fired the gun into Martin's chest.
Gorgone spent the afternoon explaining how he tested swabs from the gun's trigger, slide and holster, all of which had Zimmerman's DNA.
The slide and holster also tested positive for someone else's DNA, but Gorgone couldn't determine whose.
But Gorgone’s testimony during defense questioning about how Sanford police investigators mishandled key evidence in the case, possibly destroying evidence, further undermined the state's case, according to WFTV legal analyst Bill Sheaffer.
During cross-examination, defense attorney Don West got Gorgone to admit that Sanford Police Department's sloppiness in storing Martin's damp clothing in plastic could have compromised his findings.
“Once that DNA is degraded into pieces, that's going to affect my ability to see results when I look at that DNA profile,” Gorgone said.
Gorgone testified Zimmerman's DNA was found on the inside of Martin's gray sweatshirt, under the hoodie, but he went on to say he couldn't identify all of the DNA found on Martin's clothes.
Martin's damp clothes were packed in plastic and developed an odor, which might explain why the state has enclosed them in wood and glass frames.
Sanford police handled the gun without gloves and Gorgone said he couldn't vouch for how the evidence was stored before it got to him.
The prosecution moved on to the red jacket Zimmerman wore the night he shot Martin. Gorgone analyzed 17 different stains, and Zimmerman and Martin's DNA was found.
West got Gorgone to admit humidity, moisture and/or rain could have wiped off some of the DNA on Zimmerman's gun, jacket and Martin's hoodie and sweatshirt.
Prosecutors in Zimmerman's second-degree murder trial told Judge Debra Nelson on Wednesday that the state could rest its case by day’s end, but that didn’t happen. The trial will resume Friday at 8:30 a.m.
Prosecutors on Wednesday also presented evidence about Zimmerman's work in a college criminal justice course, which they said shows the neighborhood watch volunteer knew about Florida's self-defense law and had aspirations of becoming a police officer.
Zimmerman had maintained in an interview with Fox News last year that he did not know about the law.
Prosecutors said he did have knowledge of it, however, because the subject was covered in the college class. They called as a witness Alexis Francisco Carter, the military attorney who taught Zimmerman's class that covered Florida's "stand your ground" law, which says a person has no duty to retreat and can invoke self-defense in killing someone if it is necessary to prevent death or great bodily harm.
Carter described Zimmerman as one of his better students and said Zimmerman got an A in his class.
Under cross-examination, the defense caught the prosecution off guard by asking Carter for more details about the "stand your ground" law.
“You don't have to wait until you're almost dead before you can defend yourself?” asked West.
“No, I would advise you probably don't do that,” Carter responded, prompting a bit of laughter from those in the courtroom, including Zimmerman.
Carter gave two definitions of legal concepts that seemed to bolster the defense's case. He explained that a person can make a self-defense argument if the person has a "reasonable apprehension" of death or great bodily harm.
"It's imminent fear. The fact alone that there isn't an injury doesn't necessarily mean that the person didn't have a reasonable apprehension or fear," Carter said. "The fact that there are injuries might support there was reasonable apprehension and fear."
Carter also explained the concept of "imperfect self-defense," when a person is being threatened but then counters with a force disproportionately greater than the force used against them.
"They would have the right to defend themselves?" said West.
"Right," Carter said.
“I bumped you and you reacted in great disproportion to what I did. Then it turns and then you could put me in fear for my life and then I would have the right to defend myself at that point even though I'm in, hypothetical, I might have started it,” said West.
“Yes,” Carter responded.
Sheaffer said Carter, the state's witness, basically told the jury how they could acquit Zimmerman in the deadly shooting.
“It's always damaging when you have a witness of this caliber that has presented your closing argument to the jury and their prosecution witness,” said Sheaffer.
Another instructor, Seminole County State College professor Scott Pleasants, testified that Zimmerman had taken his online criminal justice class. Pleasants' testimony via Skype from Colorado, broadcast live on television, was interrupted when he started getting inundated with Skype calls.
Nelson also ruled Wednesday that prosecutors can show the jury Zimmerman's job application to a police agency in 2009 and his application to ride around with Sanford police in 2010.
Lt. Scott Kearns of the Prince William County Police Department in Virginia testified that Zimmerman wasn't initially hired because of a less-than-stellar credit history.
Zimmerman is charged with second-degree murder in the shooting death of 17-year-old Trayvon Martin last year. Martin was black; Zimmerman identifies as Hispanic. The case sparked nationwide protests and touched off a debate about race and self-defense.
Prosecutors have sought to portray Zimmerman as a vigilante who profiled the teen as he walked home from a convenience store on a rainy night.
Prosecutors also began a detailed questioning on the forensics analysis performed on Zimmerman's gun after calling Florida Department of Law Enforcement analyst Amy Siewert to the witness stand. She testified that residue and tearing on Martin's sweatshirt showed Zimmerman's gun was touching Martin's chest when it fired.
Siewert also demonstrated for jurors how the gun is fired by holding the 9 mm semiautomatic handgun, and under cross-examination, said the gun was safe to carry around loaded because it won't fire unless the trigger is pulled.
Prosecutors said Zimmerman's ability to understand criminal investigations and desire to be a police officer doesn't show wrongdoing, but is relevant to Zimmerman's state of mind on the night Martin was killed.
"He has applied to be a police officer before. He still wants to be one, according to some of his homework assignments
... It his wasn't some sort of passive thing," said prosecutor Richard Mantei, who noted Zimmerman took a course on how to be a good witness and expressed a desire to go on police ride-alongs. "This is simply a fact the jury ought to know."
When he was interviewed by detectives, Zimmerman spoke "in written police jargon" and talks about "justifiable use of force" and says he "unholstered my firearm, not 'I pulled my gun,'" Mantei said.
Defense attorneys believe the items are irrelevant and asked the judge not to allow them.
Defense attorney Mark O'Mara said Tuesday that if prosecutors start bringing up Zimmerman's past, the defense will dig into Martin's past, including fights. The judge had ruled previously that Martin's past fights, drug use and school records couldn't be mentioned in opening statements.
"There is no relevance and the suggested relevance will be far more outweighed by the prejudice," O'Mara said of the evidence admitted Wednesday.
Follow Kathi Belich on Twitter at @KBelichWFTV for gavel-to-gavel coverage of the trial.