>> reporter: defense team bob norgard and cheney mason were relentless in their cross-examinations of witnesses, starting with the investigators who gathered evidence. 12 bullet casings, for instance, told them nothing about who loaded the guns. >> with respect to the casings, no fingerprint evidence linking those casings to mr. serrano? >> that's right. >> reporter: no serrano fingerprints found anywhere around the crime scene. >> not a single fingerprint was linked to mr. serrano in that building, isn't that true? >> none of the fingerprints were linked to him. >> reporter: the dusty shoeprint seemed to be serrano's shoe size. >> can you tell me how many shoes there are that match -- >> no, i cannot. >> 2 million, 10 million, 100 million? do you know? >> i really don't know. >> this is all part of a circumstantial case. you have to believe each link in the chain to get him to make that footprint in the chair. >> what is the theory here? there are three men in there, 200-plus pounds each. excuse me, fellas. i need to borrow this chair so i