>> it's just amazing that someone has this kind of memory, this kind of recall that can pinpoint these guys. >> from the beginning, this would be a case driven by memories, indelible images like the scene at the soccer field. >> the blood was against the snow and then refrozen, and it was just a bizarre, very bizarre scene. >> so you couldn't have prepared yourself for what you were about to see? >> no. we identified with a lot of these victims. they could be your children. they could be your brother, your sister. this is just so wrong. >> four young victims, barely clothed, shot execution-style. >> this didn't belong in wichita, kansas. this belonged in some war zone. >> when detective kelly otis arrived at the hospital trauma room, the survivor, the woman we've called h.g., was surrounded by doctors, nurses and technicians. >> her head is bloody. her face is kind of away from me