>> wayne williams flunked all three questions. >> i said, well, this test reflected that you did kill nathaniel cater and it was his body you threw off the bridge that night. >> the polygraph measures sweating, the heartbeat, blood pressure, all rise with tension. >> you breathe a little faster. you have a hard time getting your breath. you sweat a little more. he did all those. >> wayne williams took the test three times. he failed each time. >> i said, some reaction like i'll be darned, you're the guy we've been looking for for two years. it surprised him that he didn't beat that polygraph test. he was convinced he could beat a polygraph test. he sat there and studied it and said what's this question right here? i said that's pretty good. did you cause the death of nathaniel cater. then he said, what's this question? i said did you throw his body into the chattahoochee river.