>> 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