and ken kratz began chronicling his case.l people know the least about in this case? >> the book is about steven avery that is setting forth a better representation of what the real evidence was. >> better, he says, than the way the evidence was presented in "making a murderer." in his book, krats laid out his complete theory of the case with new details he had never shared before. for one thing, kratz told "dateline" he believes steven avery had set his sights on teresa halbach in the weeks leading up to her murder. >> as we move closer to october 31st, we see steven's behavior changing. >> as kratz got "auto trader's" records, he learned teresa had actually made five earlier visits to the avery salvage yard to take photos, some at steven avery's request. >> he starts making calls directly to teresa halbach rather than going through "auto trader." >> and kratz determined on the day before one of these visits, avery purchased these shackles and handcuffs. when teresa arrives -- >> he answers the door wearing a small white tow