Dateline | May 15, 2013
>>> when sheriff's deputies entered the garage at the pyne family home, they knew right away they were working a crime scene. the back of ruth pyne's head had been bashed in by multiple blows. there were more than a dozen stab wounds to the neck. it was a case of murder, and a violent one. veteran homicide officers like greg glover and david hendrick call savagery like this overkill.
>> it's something that involves a lot of rage. typically in homicides we don't see injuries to that magnitude.
>> the intruder, for instance. the hypothetical intruder. unlikely to inflict that kind of injury to a victim?
>> very unlikely. this was something that was more intimate.
>> there were no signs of forced entry to the home. the front door was locked. the home was not ransacked. it was apparent that this was not a robbery situation here.
>> reporter: detectives did find one door in the house unlocked. the side door entry to the garage. ruth was found sprawled there on the floor. the door tight against her wrist. it told detectives whoever the killer was, he didn't leave that way.
>> if her hand was laying there, she was freshly killed, the blood on her hand is wet. for that door to have been opened up, someone leave, close the door back, and then open the door again, you would have had swiping of the blood on her hand.
>> and yet the front door the only other way out they thought was deadbolted shut. could the killer have had a key and locked it after he made his escape? it didn't seem logical if he was an intruder. but then of course bernie pyne had a house key. was the husband perhaps the killer?
>> typically in these type of cases it's normally someone that's directly involved, somebody that's inside.
>> reporter: so the night of the murder the detectives talked to bernie and his son, jeffrey, in a routine interview. bernie was up first and he told detectives about ruth 's medical history .
>> we talked about the mental illness . of course many of the detectives -- or i don't know, many of the police officers had been out to the house with medical pickups for ruth .
>> reporter: but he says he was stunned when detectives revealed to him that his wife's death was a homicide.
>> i could not believe, one, that ruth was dead and, two, that anyone would harm her.
>> reporter: then as the detectives' questioning went on bernie said something that piqued their interest.
>> the detective asked me if i had had sex with any other women besides my wife in the last six months. and that immediately caused me to be uncomfortable. because i had to answer yes to that question. and i gave them the details.
>> live girlfriend, dead wife. not a good set of facts.
>> no. it definitely threw another cast on things. i mean, as far as how the marriage was.
>> does bernie become a suspect to you?
>> absolutely. it did not appear that this was committed by a stranger.
>> reporter: bernie says now that the stress of being ruth 's caregiver drove him not only to threaten divorce but also into the arms of a girlfriend.
>> i couldn't take any more. i couldn't take battling over medication anymore. i couldn't take wondering what she was thinking. whether or not julia was going to be, you know, cared for well or something was going to happen.
>> reporter: ruth discovered the affair one night when she and her daughter walked into the same restaurant where bernie was having dinner with his girlfriend. the mistress broke off the affair. and ironically, being caught red-handed that way, bernie says now, not only saved his marriage but brought ruth around to taking her meds.
>> ruth i think realized maybe that she had pushed me too far, and that's when she told me, she goes, " bernie , i will do anything to save my marriage and to save my family." and i said, "that means you will take your med kaugs aication and you'll let me watch you take it."
>> reporter: but now his wife was dead, and bernie was giving police an alibi, accounting for his time the afternoon his wife was murdered.
>> bernie was at a restaurant with co-workers and friends. bernie gave us the times that he had left there and that he had went to pick up his daughter, julia, like he always did. and to the point of when they arrived home.
>> reporter: ruth 's sister susan didn't believe bernie could possibly be involved. after her initial shock she began to wonder whether some mental patient from ruth 's trips in and out of hospitals over the years had developed an obsession with her.
>> ruthie was so beautiful that i could see someone being infatuated with her. and she did give her address and phone number and things out to some people. so it wouldn't have been hard to find her.
>> reporter: an interesting theory, maybe, but the detectives' experience with killings like this told them to first keep looking at people who knew ruth very well.