was the person who killed diane kyne. reporter: the defense argued that bill s story was not true and that his dna was all over the crime scene. the dna on diane s neck, the dna on the pillows, the dna on the folded sheets, to me, was a slam dunk. that s reasonable doubt. reporter: the defense offered a theory that kevin s blood had sprayed toward the bed after he was scratched by bill in their fight at the door. the defense also argued that bill was the real killer. if it s not our guy, it has to be him? we did say that. i don t know if it was just not as aggressively as it needed to be said. reporter: maybe if they d hit bill harder, jurors would have found reasonable doubt. but they didn t. after four hours, the jury came back with a verdict guilty. second-degree murder. kevin kyne was sentenced to life in prison. my throat went down to my ankles. i mean, it was a horrible feeling. there were no winners.
for his mother s murder is obvious. she was worth more dead than alive to his step-dad. let me hear your indictment for bill kyne for murder. kills your mother why? money. $750,000 could help him out a lot. reporter: detectives thought they had a plausible motive. now they combed through bill s 911 call and his lengthy interview on the day of the murder. not everything seemed to add up. reporter curtis krueger noticed something curious reported by the first deputy at the scene. the first responders arrived, and attempted to take a pulse of diane, and they found her body to be somewhat cold. and that, of course, indicates that she may have been dead for a while. reporter: that deputy arrived just minutes after bill said he d caught kevin in the act. diane s body temperature may have suggested a different timeline. detective beining was troubled by another part of bill s story. he said he never went back to check on diane after kevin ran off. i assumed that she was already de
him in. he was arrested, charged with killing his mother and held in jail. but that wasn t the end of the story. not by a long shot. remember, bill kyne had flunked his lie detector test. kevin, meanwhile, had also agreed to be wired up. they asked you the critical questions. oh, of course. all around one question, did you kill your mother? exactly. you passed the polygraph test. yes, sir. passed it, flying colors. when the polygraph stuff came back, your thought was, we may have the wrong guy in jail here. reporter: the prosecutor acted quickly. he handed kevin a get-out-of-jail-free card, releasing this accused killer back into the community. i felt as a prosecutor, and my goal here is justice, that i thought it would be wrong to have kevin sitting in jail with with the status of the case at that moment. now, that doesn t necessarily mean we had enough evidence to put bill in jail. reporter: so the prosecutor convened a grand jury in early 2011, hoping to sort
do you realize this now looking back? oh, i was fully aware at the time. reporter: it was a light moment and just what bill needed. only eight months earlier, he d become a widower. my wife, krista, she fell in the middle of the night. they say she hit her head and she drowned in the pool. i pulled her out of the pool easter sunday morning in 2000. i pretty much fell apart. and there i was a single dad, trying to raise them and, you know, keep the family going. he loved my mom. he loved her to the moon and back, and then he lost her. he was just lonely and you could see it in him. and my brothers were definitely egging him on to get out and meet somebody. reporter: and in diane, bill met somebody special. diane comes into the picture and he has this beautiful woman and now she s taking care of him. he was in love with her. he needed that. he needed her. she was actually what i consider my dream girl. blonde hair, blue eyes, and just a beautiful person inside and out. wh
911 calls. two dramatic stories describing a cold-blooded murder. only one of them could be true. coming up did you lie? i did not lie. a polygraph, dna and the curious death of wife number one. bill had a wife that drowned in the pool. was bill kyne becoming suspect number one? when dateline continues.