if i can solve this, i can probably put the whole thing together. >> the anomaly -- well, that would be the puzzling piece of evidence which haunted investigators for almost two decades, that odd oblong hunk of foam. >> i knew it was either going to come from robin, the victim, or it was going to come from the suspect in the case. and once i was comfortable that this didn't come from robin's purse, it didn't come from robin's clothing, it's not part of kentucky fried chicken's restaurant, it doesn't belong there. >> which left only one other possibility -- the murderer. wallace pored over the pictures of the one suspect, marshall, when he was pulled over the week earlier, and suddenly a light went on. >> he's wearing his clothing still, of course, and he has a pair of work boots. and his work boots, sure enough, i can see just enough from the pants being hiked up that i think i wonder if these are the kind of work boots that have that big fat -- couldn't be. couldn't be. >> could it be the foam?