Dateline | June 28, 2013
>> reporter: the death of kay mortensen was horrific, humiliating. helpless to defend himself inside his own sacred port res. the keller had bent him over the bathtub, slashed his throat several times, and all the guns never fired. it seemed so -- personal. sergeant eric knudsen , got a briefing from the first officer at the scene who turned on his audio recorder when he met kay 's son roger and roger 's wife pam . roger had found the body and was already suggesting possible killers.
>> he told me he had an appointment for lunch at noon with a guy named mike kinn discussing $25,000 worth of guns.
>> reporter: mike kipp, mike was kay 's former student.
>> roger and pam identify him real quick. they say he's involved. he owes my dad money. he is the one who did this.
>> reporter: roger told detectives kay , holding a collection of meek's wike's weapons, 30 of them. pistols, rifles, shot guns. kay put the guns in his bunker. roger thought there might be a grudge involved. when detectives went to look for the guns they were gone.
>> so we pull in michael kipp that night too. we interview him. we can get his alibi, it's quick.
>> nothing suspicious about it. it turned out. mike had nothing to do with kay 's murder. he simply needed money and kay agreed to buy his guns. by now, tips were coming in.
>> this female said it is the baker boys. she said the baker boys did this.
>> reporter: the baker boys were brother whose fairly or not had developed a reputation as the town's troublemakers. detectives found them. they had solid alibis. then the next day, another tip. a woman who implicated her own husband.
>> he came home last night the time frame before the homicide. grabbed a bunch of stuff, including a knife. he has been looking for guns. i know he is involved.
>> reporter: the woman's husband was eventually eliminated as a suspect. detectives hoped maybe the stolen guns would lead to kay 's killer.
>> we recovered a lot of firearms thament wet were stolen. none linked.
>> reporter: that highlighted another aspect of the mystery. kay remember collected firearms, close to 100 valuable guns locked up in his house. yet the thieves just stole the cheaper ones from the bunker. pretty bizarre robbery to take those guns and not take the far more valuable collection that kay had.
>> reporter: in fact, the inside of kay 's house was pristine, untouched, no sign anybody had stolen anything. if this was a home invasion , it was an odd one. but by then, truth be told, detectives were homing in on the two people who admitted they were there the whole time. kay 's son roger and his wife pam .
>> you sure he is dead?
>> reporter: starting with the 911 call they made. something odd about it.
>> it didn't sound how i would think that a phone call should be made to 911 after discovering your father had just been killed with the throat cut and zip tied in the bathtub.
>> reporter: roger and pam said the detectives appeared to be unemotional. uncaring, even callus. even though they claimed that gunmen stood over them, kept them hostage for all most two hours, at first pam couldn't seem to describe the men. a
>> okay the guy that had the gun, what did he look like? a white guy? black guy? hiss p hispanic?
>> i don't know.
>> she seemed uncertain about the number of gunmen.
>> how many guys were there?
>> could have been three.
>> look what happened next. roger took the phone and changed the story?
>> were they white, black, hispanic.
>> they were white.
>> three white males.
>> two white males.
>> roger explained the reason for all the confusion, if they ever revealed what their captors looked like they would be hunted down and killed. did you buy that?
>> not really. i didn't they didn't appear fearful. they were saying it. but they weren't really acting fearful.
>> reporter: anyway, why would vicious killers not have killed them too? night of the murder, knudsen interviewed them. my name is eric knudsen ? did they seem nervous? agitated?
>> neither. just unemotional.
>> reporter: even cold toward the victim.
>> he is a cantankerous old farther.
>> reporter: as they told their stories, detectives started noticing subtle differences.
>> and they had blue fuzzy gloves. looked like women's winter driving gloves or something. the fuzzy kind.
>> they had, i know they had purple gloves on. purple, you know, medical gloves .
>> reporter: lots of details on which they didn't agree. so sergeant knudsen decided to employ a well known police interview technique. he got tough, accusing. quite frankly, i think the story is a bunch of crap. the story is a bunch of crap that you and roger have come up with.
>> i'm sorry you don't believe me. does it sound too rehearsed or?
>> reporter: i want them to say i had nothing to do with this. detective, you are crazy. i had nothing to do with this. that's what i wanted to hear. it never came out.
>> reporter: listen to what did come out?
>> is your husband capable of killing somebody?
>> i would hope, i mean, i wouldn't think he is. i wouldn't think he is capable of killing his father.
>> reporter: a search of roger and pam 's home showed they appeared to be in financial troubles. detectives found selection notices and unsent mortgage coupons suggesting at lowest they were behind in their house payments.
>> i know we are in a lot of debt. but we -- we -- i personally would not have my father-in-law killed for his money.
>> reporter: and yet as roger told the detective.
>> but i get a big share of my dad's millions too.
>> reporter: within days of the murder, pam and roger agree to go back to the house with detectives for a video retelling of their intruder story.
>> go ahead.
>> at the front door, my wife was holding a pie right here.
>> that provide you any useful information?
>> it provided useful information from our standpoint. as far as more circumstantial evidence that they're not being 100% truthful.
>> reporter: once again, detectives heard foggy memories. she knocked on the door or rang the doorbell. i belief she knocked on the door. theydialogue, a bad crime movie.
>> he pointed at us. you are here at the wrong time, put out your hands.
>> reporter: then there was that same strange lack of emotion. when roger described what should have been the worst moment of his life.
>> i left. i came back downstairs. my wife was talking at the time to -- 911 dispatch. and i said "he's dead."
>> reporter: roger and pam took a polygraph test . and what do you know, roger was found to be deceptive. and pam -- was jumpy. the operator couldn't complete the test. still, roger and pam swore up and done they had nothing to do with it. they were victims themselves. truth be told, the police needed some real evidence . and out of the blue, something arrived.