tom bevel, a blood spatter expert hired by dr.ilton, agreed with gardner's assessment. >> the spatter places the shoe within an area capable of receiving spatter, and the spatter is being generated by some impact into a blood source, which, in this case, is mrs. hamilton. >> and blood spatter found four inches up inside of his right shirt cuff was most telling. it was direct spatter, meaning the blood landed directly on the shirt. for spatter to get up inside the cuff meant it had to be traveling at some speed. >> for it to get on the inside, the blood has to be coming at an angle capable of missing the wrist and the edge of the cuff and the outside and going on the inside of it. that puts very limited positions with which that could have occurred. >> the only way that could have happened is from somebody using their hand to either hold a weapon or something like that, and beat -- beat susan hamilton and the blood droplets come spewing off to be driven up in that angle. >> scientists performed dna testing on each and every bloodst

, brenda andrew played in her husband's murder, investigators sent her blood-stained clothing to tom beveler analysis. bevel noticed that many of the blood stains on her jeans had an elongated shape, consistent with blood dripping from her arm on to her pants. >> we have some low-velocity blood drips, that would be blood that is breaking away primarily due to gravity dripping down on to the jeans. >> dna tests confirmed this blood was brenda's. but bevel also found mist-like blood spatter on brenda's jeans below the knee, which had penetrated deep into the fabric. >> it is from a high-velocity occurrence, such as a gunshot, in this case, multiple gunshot pellets that has spattered the blood traveling back from him, referred to as back spatter, and then subsequently, landing on her clothing. >> dna tests confirmed that this was rob's blood. this proved that brenda was standing only a few feet away from rob when he was killed. >> the back spatter on the pants, i think that gave us that one bit of evidence we needed in order to put that gun in ms. andrew's hand. >> prosecutors believe brenda