. >> michael baird, was this that kind of moment, bum, bum, bum, or just falling flat because, of courseara and his team got ahold of this witness and did cleanup? >> yes, great question. fingernails are often times a great source of biological evidence in a situation like this. but a lot of things can affect whether or not there is anything there. they found nothing other than trayvon martin's dna under the nails. >> does that speak to the prosecution's case? does that speak to the defense case? can anybody explain it away? >> there is a number of possibilities. it could mean that he didn't have his fingers extended if he was fighting with george zimmerman because typically under your fingernails you get skin from scratching someone. so if the fingers were extended that would happen. if they weren't extended, you wouldn't get that. >> this is a story about punching, not scratching, so perhaps that is a bit of a wash. >> right. >> who knows how the jury will take it, though. this next moment may be more significant because it involves the murder weapon. george zimmerman maintained an, oh