alive. i didn't know. that's when i had the knife. and to make sure, had cut her throat. >> reporter: then, bennett said he wiped the place down. and to throw forensics off he ransacked the bedroom and used heidi's lipstick to make that number one on the living room wall. after that, bennett says, he fled. that's it? >> that's it. >> reporter: heidi's dead. >> heidi's dead. >> reporter: detective childs pressed who was the client? he showed bennett a photo array of six suspects. assistant state attorney matt breault. >> he immediately separates four photographs and says, "it's definitely not these four." and he's left with two. and he takes a couple of moments and stares at them. and eventually, he says, "yes, this is him. i remember him." >> this one.