peggy and craig gustafson both were convicted for their role in mr.s murder and will serve a minimum of 22 years in jail. r.d. cheely and doug gustafson received additional life sentences. in the end, a half dozen families were destroyed and prosecutors believe there would have been more victims if forensic science hadn't ended cheely and gustafson's killing spree. >> you can't just take the science by itself and build a case, or rare occasions can you. you use a combination of what are people telling you, what do you know about this person, that person, and you use your science. and it all just meshes right together. and it builds your case. but without that, you know, we'd still be back in the dark ages of investigating crime. >>> two women from the same town killed in the same way suggested a serial killer was on the loose. there were unusual metal fragments on both victims. and investigators needed to find out what they were in order to stop a killer. >>> the spirit of washington was traveling from seattle along the shores of lake washington when