it s huge. reporter: especially when his dna was found on it. the evidence was stacking up against steven avery and fassbender says that rav4 would later them investigators one last thing. we tested the hood latch and found dna matching avery on the hood latch. reporter: avery had explaining to do. nine days after theresa s disappearance he and his partner brought avery in for an interview. we obtained the video. he was in your bedroom. you know the key is there because you put the key there. reporter: avery was defiant and claimed cops were framing him, planting evidence. no way. the cops put that evidence there. reporter: they weren t buying it and placed steven avery under arrest arrest. i didn t do it. somebody s doing a good job on me. reporter: investigators were
that s the only way the key gets there. avery was defiant and claimed combs were framing him, planting evidence. the cops got the evidence. fastbender and wiegert weren t buying it and placed steven avery under arrest. i didn t do it. we re not do somebody is doing a good job on me. investigators were convinced they had their man. still, they didn t know how or why teresa had been killed. coming up shackles, handcuffs, strange behavior. teresa s creeped out. could something in his past have led him to murder. when dateline continues. i m so frustrated. i just want to find a used car without getting ripped off. you could start your search at the all-new carfax.com that might help. show me the carfax. now the car you want and the history you need are easy to find. show me used trucks with one owner. pretty cool.