Dateline | January 31, 2014
>> narrator: in the days after the murders, two families, the lockharts, uncles, aunts, nephews, nieces and kim's family were united in grief.
>> we lost three wonderful people that we love dearly. we don't have them with us today.
>> kim, bradley, jill, all gone.
>> narrator: david was all but shutting down.
>> i'm a mess, i'm on medication, i'm having to buy caskets, i'm having to buy burial plots, i've got all this stuff going on.
>> narrator: three days after the murders, the indiana state police called david in for a second interview. he sat down with two cops he newell. he had been sharing coffee and cases with them for years.
>> because of the high profile of this case, and because of obviously you know the notoriety notoriety --
>> this time the tone of the interview had changed. because now the investigators did have a working theory of the murders. and the evidence they were gathering pointed to none other than david camm as the killer. their one-time fellow trooper, their law enforcement brother, was now quite possibly their man. a monster who had murdered his family. they had a timeline, the murders took place, they believed, between 9:15 and 9:30 that night, after david returned home.
>> people heard something they thought was unusual. when we talked to them, they said it sounded like gun fire.
>> narrator: the police canvass had turned up a neighbor who heard shots fired.
>> they noted the time, the time was when you were already home. the time was 9:20, shortly thereafter.
>> david saw where this was going and pushed back.
>> i'm just telling you what we -- you know.
>> it's wrong, it's wrong.
>> people are making this up?
>> i'm telling you people are confused.
>> narrator: the investigators account had david camm square in the crosshairs. he came home from basketball and killed his family.
>> it's not right. it's not right. it's not right. it's not right, guys. it's not right. you're wrong. you're wrong, wrong, wrong. you're wrong, darrell. you're wrong.
>> well --
>> this is not right. you're getting off the track. something's not right here. now think.
>> narrator: they told david about physical evidence they collected, specs of blood, barely visible to the naked eye on the bottom of the t-shirt he wore that night. the crime scene already told them the husband and father did it.
>> blood on your shirt and i had it dna analyzed. this is scientific documentation, the only way that comes on is from blow back, or blowout from a gunshot wound.
>> blood spatter t case against david camm .
>> that is supposed to be on my t-shirt that i played ball in?
>> wrong, darrell. wrong, guys.
>> what do we do when they tell us that? now we got to figure out why.
>> you better find another expert.
>> narrator: but the cops had full confidence in their man.
>> i rely on this man and he's very -- he's renowned as far as his expertise. this is not something he just started to do yesterday.
>> narrator: the noose was tightening even as david protested.
>> the t-shirt that i had on was what i had on. that's what i wore over and that's what i wore home. and any blood that got on it now came from either an impression of something i leaned on in the car or it came o.f
>> narrator: signs of a cleanup that had to be david .
>> there's signs that there was a cleanup.
>> that's ridiculous.
>> what about the bleach, david .
>> no, no, no, no, no, no, no. no. no. i didn't clean up [ bleep ] somebody may have. but it wasn't me. that person is your suspect.
>> narrator: and there was something disturbing, the medical examiner found when she looked at jill t young daughter. signs of blunt trauma in the genital area. to them that meant one thing, that david camm had molested his daughter.
>> it happened that day, that night, that's when it happened, and it wasn't by me. you guys are wrong. i did not do this. i did not do this.
>> who did do it?
>> i don't know. that's why i called you guys. that's what your job, that's what you're supposed to be doing. you're looking so hard at me.
>> we're looking at everybody, david .
>> but you're still off base. you're so wrong. you're so wrong, mickey.
>> an arrest warrant issued out of floyd superior court .
>> narrator: hours after his second interview, the indiana state police arrested david camm and charged him with the murders of his wife and two children. it had been three days since the shooting.