Dateline | March 28, 2014
>> narrator: steve democker was in jail, charged with first-degree murder for his ex-wife carol kennedy 's violent death. he pleaded not guilty. private investigator rich robertson joined steve 's defense team and right away saw what he believed was an elemental mistake by detectives.
>> they put together their story, their version of events, almost immediately.
>> the husband always does it, right?
>> they focused in on one person and they had a stooir, and that's what they worked on. they zeroed in on steve democker right from the very beginning.
>> narrator: the man who lived at the guest house and showed up at the crime scene within minutes of the officers and was the first person to point the finger at steve .
>> the fact that law enforcement viewed him in a different way than they viewed steve democker. that they saw jim knapp as a friendly witness and they see steve democker as a suspect, frames the way they investigate. so anything having to do with jim knapp becomes excusable, explained, it's just not something you have to worry about because he's not our guy.
>> narrator: and yet, look for example at these crime scene photos at carol 's kitchen counter , the magazine was sitting on it. and slipped inside between the pages were some financial documents that were printed the very day carol was murdered.
>> that became really important because his thumbprint is on those financial documents.
>> narrator: what was jim knapp doing with these documents? and something else, perhaps very significant.
>> there was blood on the doorknob of the door that led from the main house to the backyard garage.
>> so whose dna was mixed with carol 's blood? jim knapp 's dna .
>> just like the thumbprint, the question becomes when did jim knapp 's dna get put on that door handle ?
>> narrator: robertson clearly had his suspicions.
>> so you think jim knapp should have been investigated and was not?
>> narrator: he told police he was nowhere near his house when the murder took place.
>> what the son said was, yeah, they had gotten the video and the son was watching it. he doesn't know where dad was.
>> dad wasn't sitting beside him in the room?
>> no, dad was not watching with him. so he doesn't know where dad was. the son got bored watching this movie. and i believe he went and got on his computer. so there's a period of time that we don't really know. he might have been in the house. but nobody saw him.
>> so maybe knapp 's solid alibi wasn't. and remember how he told everyone he had cancer? sharon, a doctor, discovered something about that.
>> i have seen the medical records .
>> he had a superficial type of skin cancer at one point and it had been removed. so no, he didn't.
>> steve 's family even recorded this video, after the murder, in which jim knapp said things about carol they found deeply disturbing.
>> carol and i lived our life like an old married couple.
>> he was actually rather obsessed with carol . i have e-mails that he's written about how, what he and carol share is more than anyone could picture that no one will understand the bond that they have and how close they are to each other. he referred to some people as his girlfriend. but she never had any romantic interest in him and no one has ever --
>> he had a tremendous romantic interest in her?
>> very much so.
>> thus in your mind, a reason to be angry at one another?
>> narrator: was it possible that carol rebuffed him, that he got angry? the detective didn't ask those questions, and then it was too late. six months after carol 's murder, a 911 call from a condo where jim knapp moved to live after carol 's murder.
>> the doors open, it looks like a gunshot, holes in the window and there's a shell casing inside and the bedroom door's closed.
>> who are you doing the welfare check on?
>> jim knapp .
>> jim knapp was dead. gunshot wound . the medical examiner ruled it a suicide.
>> i was stunned. it was one of those moments where it just sort of took my breath away. and then when i found out there was no note, and as i learned about the details of what the scene looked like, it's still a baffling death.
>> narrator: baffling because it simply did not look like a suicide.
>> there was multiple gunshots, there was furniture in disarray, there was drawers pulled u out.
>> narrator: just as investigators believe someone staged carol 's murder. it could. have been steve , he was in jail. and then the questions multiply. in june 2009 , almost a year after carol 's death, steve 's attorney received an e-mail, the sender anonymous. the e-mail read, i can tell you what really happened the night kennedy was killed. the e-mail said jim knapp was running his mouth to kennedy about a prescription drug deal he was in. it said the murder was meant to look like home invasion roche gone mad. steve replied with a startling story. he had heard the same thing. just a month earlier, in jail.
>> steve said that somebody was communicating to him through the ventilation system in the jail. and told him a story about how a drug ring out of phoenix had been trying to collect money or seek some retribution against jim knapp for involvement in a prescription drug ring.
>> narrator: the attorneys arranged for a meeting, an opportunity for steve to tell law enforcement what he heard so they could investigate it. they showed him the mysterious e-mail. listen to his reaction.
>> i'm sorry.
>> i hate to ask you this, but can you explain why you're getting emotional here today?
>> because i spent a year not knowing what happened. to carol . and being accused of it. that's what's happening right now.
>> narrator: there was more than the e-mail to go on. remember the dna the medical examiner found under carol 's fingernails? turned out, it wasn't steve 's. or jim knapp 's. police called the dna evidence item 603. but to investigator rich robinson , it meant much more.
>> evidence item 603, became mr. 603. it was a male dna that was found mixed in with carol 's blood, under the fingernails of her left hand. this wasn't a small amount of dna . a reasonable person would think that this probably could have gotten there during an attack.
>> the anonymous e-mail, evidence item 603. steve thought investigators should focus more on all of these things. but it seemed to them, prosecutors had already made up their minds and steve would go on trial for murder.