. >> as investigators headed off to check reginald pott's alibi, down in calumet city, officer calvincruising vacant parking lots. this time a mile or so from where he found those boxes when a partner noticed something. >> he saw a pair of ear buds hanging from the tree. >> bright little bobbles showed up in the dark. what else was in that abandoned place? at the end of the midnight woods. >> coming up, it's now a different type of investigation. and detectives take a closer look at a man from nailah's past. >> she sensed there was something off about him. and that's probably where she decided to, you know, look a little deeper. >>> when "dateline" continues. ♪ [ screams ] ♪ [ laughs ] ♪ whoa, whoa, whoa. your one item would be the name your price tool? it helps people save on car insurance. why wouldn't it save me? why? what would you bring? a boat. huh. i'm ray and i quit smoking with chantix. i tried cold turkey, i tried the patch. they didn't work for me. i didn't think anything was going to work for me until i tried chantix. chantix, along with support, helps you quit smoking. ch