i'm thinkin', "holy cow." >> reporter: three weeks before heidi's murder, an officer had spotted alexander bennett walking down a baltimore highway. >> when a wanted check is run by a patrolman or an officer that check remains in the computer forever. >> how important was that? >> incredibly important. >> reporter: detectives meyer and childs hopped a flight to denver. it was time to meet this alexander bennett. >> coming up -- a suspect's story, a surprise to even these experienced detectives. >> i've got to tell you it's strange. >> that's why it is strange. >> when "indiscretion" continues. strange. >> when "indiscretion" continues. st drive works. they give their customers seven days. and if they don't like it, they give 'em their money back. wait, they take the car back? that's crazy! what if it was driven by like a zookeeper? or a mud wrestler? or a guy who's on the outs with the missus and he just needs a place to sleep for seven days? yeah. (vo) buy your car online. love it or return it. with carvana.