I'm eager to listen to that MS episode tonight. ("Nobody in Las Vegas seems to remember Keegan Kline.") It fits with what I've thought about KAK--and so far I haven't heard any mainstream news items about what KAK's family and friends think about him, former employers, etc., and nothing about the supposed Las Vegas trip(s) to speak of--flight information, arrival and departure dates, hotel(s).
I hate to slag on the guy, but it looks very much to me that he's a sad case, we haven't heard much from friends and former employers and coworkers, because he has very few friends and former employers and coworkers. All that nonsense about being an "armed security guard" in government facilities and parks, about being a croupier (or whatever it was he claimed on FB) at a big casino--that's the life he fantasizes about. In reality, he's a guy with no job, sleeping on friends' couches, scrabbling together a few bucks to buy weed or get a fast-food burger ...
Honestly, I really *could* picture him as the murderer (or one of them) at Delphi, except that, as somebody else pointed out, he hardly would have given up a DNA sample without a warrant, if he suspected his DNA might be somewhere at the crime scene. IMO, that is.
Lee Harvey Oswald failed at multiple jobs, had an unhappy marriage, lived in near-poverty, had no friends and no real social life, and felt (justifiably) like a loser, multiple books confirm this. He tried to kill a far-right-wing retired general, and then killed a liberal progressive president: he did not care WHO he killed, he was just desperate to show that he wasn't just a zero. Honestly, I could see KAK feeling the same way and deciding to be a "thrill killer" ... again, I think the DNA sample makes it very unlikely he IS L&A's murderer. But I can definitely picture him as one.