i asked him if he'd ever had any problems with ken moore. >> see on that guy, he was trying to get a an 20. >> he says that he remembered trying to strike up a deal to cut ken's lawn, that ken tried to get a lower price, they had a little bit of an argument, and that he had left. i had to check his shoes as well. remember those footprints? i had to make sure his were or weren't those footprints. >> okay. they weren't the same. after he was interviewed, we left the house. jeff and i met back up. mark, i'll meet you back at texaco. >> i didn't get a bad feel from him. he seems like a harmless, pretty mentally challenged guy that, you know, walks around all day long, trying to make a few bucks. >> we both agreed. he wasn't our guy. but there was another lead. >>> coming up next, vital leads from the victim's sister. >> but i think he should be questioned. what did he do? usa prime credit... this peggy... hi, i'm cashing in my points... peggy? no more points - coupons now. coupons? coupons. coupons? next, you convert coupons to tokens. tokens? then you trade tokens for credits. and then i