jd spielbauer (on phone): no, sir. ): coming up. there are some things you just shouldn't lie about. what kind of person, in your view, does that? a liar, a fraud. charlatan. josh mankiewicz (voiceover): who was jd really? if he's trying to set her up, he's either the worst setup artist in the world, or he is the most sophisticated criminal there ever was. josh mankiewicz (voiceover): when "dateline" continues. stop being sneezy without feeling sleepy. get 0% brain interference for fast. >> non-drowsy allergy. >> non-drowsy allergy. >> relief with ugh, weeding is the worst. but now, there's spruce: you'll see visible results in 1 hour and dead weeds in 1 day and it's safe for use around people and pets. spruce: the new, hard-working, worry-free weed and grass killer. ♪ it's spruce! ♪ internet. >> with one click. incogni stops identity thieves. >> and protects your privacy. >> turn on one. switch to limit unwanted robocalls. >> and spam emails, and to reduce exposure to data breaches. switch on peace of mind. go do you h

jd spielbauer cheated on robin with katie, divorced robin, married katie, then cheated on katie with mation to share, investigators were eager to hear it. jd began by telling them what he had before, about hanging out with his uncle ty and sending robin that text about meeting up, except this time, he provided some additional details. jd now said katie came home a little after 9:00 pm in a bad mood. talking to the again, jd said he woke up a while later to find katie gone. she had apparently taken his truck. that's when he said he started texting katie and ty and robin, who never responded. obviously, mongold wanted to know why jd changed his story. was that really why jd was coming clean? this time around, he not only admitted he had plans to meet robin that night, but also told them where, and it was not at his house as he had first said. but jd maintained, he never left his house. mongold already knew a ping from jd's cell phone was telling a different story than jd was telling. jd said he could explain that. the house. which was? that would be katie. >> okay. why would she take yo