Nightly News | July 03, 2013
>> another dramatic day in the second degree murder trial of george zimmerman . the jury got a good look at the physical evidence, like trayvon martin's clothing that night and the gun used to kill him. ron mott with the report from sanford, florida .
>> reporter: today, jurors got an upclose look at trayvon martin's blood stained hoody and the bullet hole created by the .9 millimeter pistol. a contact shot.
>> meaning the muzzle or the barrel of the gun was up against the sweatshirt when it was fired?
>> a complete dna profile which matched george zimmerman .
>> reporter: zimmerman 's were the only fingerprints on the gun and no dna of zimmerman 's found underneath trayvon's finger nails . and zimmerman aced a criminal litigation class.
>> probably one of the better students in the class.
>> 2010 course included discussions of florida 's self-defense law, commonly called stand your ground . contra vikting zimmerman 's tv interview, where he said he had no knowledge of the law.
>> prior to this incident, had you even heard stand your ground ?
>> no, sir.
>> reporter: zimmerman says he filed in self-defense. the witness testified that he taught that self-defense has its limits.
>> we talked about imperfect self-defense, where you may have started out being the person that was attacked, but for whatever reason, you took it a step forward and now you are the aggressor.
>> reporter: he told defense attorney don west the standard is imminent fear.
>> you don't have to wait until you are almost dead before you can defend yourself?
>> no. i would advise you don't do that.
>> reporter: this brought a smile and chuckle from the defendant. court closed tomorrow for the fourth of july holiday. testimony resumes here on friday. ron mott, nbc news, sanford, florida .