as we continue to monitor the developments out of cairo, a big day back home in the trial of george zimmerman in what s turning out to be a speedier trial than first predicted. the prosecution called several key witnesses. friday morning we anticipate they ll rest after trayvon martin s mother takes the stand. lots to talk about with our expert panel. we get underway right now though, with martin savidge. reporter: though a symbol to many, the hooded sweat shirt trayvon martin wore the night he was killed is also a key piece of evidence. the state expert said he found no trace of george zimmerman s dna on that sweatshirt, not even on the sleeves or cuffs nearest to the fists the defense says trayvon martin was hitting him with. and no zimmerman dna was found