Trayvon Martin's DNA Not Found On George Zimmerman Gun

The Huffington Post reports Florida Department of Law Enforcement analyst Amy Siewert also testified that tearing and residue on Martin's clothing showed the gun was directly against him when it fired.

Prosecutors have worked on portraying Zimmerman as a vigilante who profiled Martin as the teen walked to his father's fiance's home on a rainy February night.

Gorgone and Siewert were called to take the stand on the same day evidence was presented to show Zimmerman had aspirations of becoming a police officer and knew about Florida's "stand-your-ground" law.

The law states that 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.

Prosecutors say Zimmerman's ability to understand criminal investigations and desire to be a police officer is relevant to Zimmerman's state of mind on the night Martin was killed.