i'm craig melvin. investigator tom fassbender deny police framed steven avery for the murder of teresa halbach. after all, avery's nephew brendan dassey admitted helping his uncle commit the crime, a story on camera. but the teen later recanted and a closer look at the confession would put the confession at the heart of the controversy surrounding this case. here again is andrea canning. >> all the renewed attention in the steven avery saga has shed light on the other defendant in the case -- brendan dassey. the teenager had been convicted of rape and murder, but to his family, none of it ever made any sense. is brendan someone capable of rape? >> no. no. i don't even think he knew what that was at the time. >> in 2008, attorneys took up dassey's case for his appeal. they saw a mentally challenged teen with a low i.q.