with harley's dad.lbauer: i was sitting on the arm of the couch. they opened the door, and the sun was right in my face. [dog barking] [crying] my mom and my brother walked in. the tears went, puh. and they were just there. my mom was like, oh, my little baby, i'm home! josh mankiewicz (voiceover): happy ending? not yet. because if katie didn't do it, that meant someone was getting away with murder. coming up. he had multiple firearms at his disposal. he chose a sig sauer 22 pistol that had a history of jamming after the first shot was fired. josh mankiewicz (voiceover): would katie be the next victim? it was scary. i saw him drive by my house. and i had told my lawyers. he said, well, honey, you're bulletproof. and i remember telling him, as long as i'm not within rifle range. josh mankiewicz (voiceover): when "dateline" continues. in the fridge. >> it's not dog food. it's fresh pat. >> real meat. >> real veggies for. >> my boy. >> junior. >> junior. >> what are we doing here? -we're done. -what about

her daughter harley was 10 years old at the time living in florida with her father.riends one day at school. oh, my mom is so cool, i bet she's smarter than yours because i was being a little kid. so i had looked up on my science teachers' laptop, my mom's name, and it said, arrested. and i was like no, no, that's not true. it's false. josh mankiewicz (voiceover): oh, but it was true, all of it. this was katie the day she was arrested back in that little room with sergeant mongold. i did not do this. so you have nothing to offer us? that's not true. i don't know. who - do you think did it? i don't know. i'm starting to think maybe jd did. josh mankiewicz (voiceover): this was certainly not the first time investigators heard a suspect in a murder case point the finger at someone else. their reaction wasn't new, either. no. i know you know. you're not here by accident. stop yanking my chain, stop wasting my time, tell me the truth, or let's go. i did not kill robin. who did? and don't give me this-- i do not know. katie, listen to me. at this point-- at this point righ