His first known crimes were the murders of Joseph and Julie Otero and two of their children in January 1974. His method would become chillingly familiar to police: He cut the Oteros' phone line, then apparently managed to get himself invited inside the house, where he bound, gagged and strangled his victims.
BTK claimed credit for the murders in a letter describing the crime scene in detail, including the color of the victims' clothes. Though the victims were not sexually assaulted, he derived sexual pleasure from his attacks; he left semen at several of his crime scenes.
In the Otero letter, BTK warned he would kill again: "It hard to control myself," he wrote, in the error-ridden prose that would be another of his trademarks. Over the next three years, he killed at least three more women.
He reached out to police several times, once calling 911 to direct authorities to his most recent victim. Then he went silent for a quarter century. In March, he resurfaced with a new letter, this one claiming credit for an unsolved 1986 strangling.
At the time, authorities speculated that newspaper coverage of the 30th anniversary of the Otero murders had prompted BTK to seek public acknowledgment of his other killings. In the last several months, BTK has reached out repeatedly, sending a word-search puzzle to a local TV station, writing a letter to police and leaving packages crammed with all manner of clues in public spots around town. BTK marked many of his letters with a secret code; the FBI was able to authenticate several of the recent communications.
In one, he included an outline for his autobiography. It ended with Chapter 13: "Will There Be More?" Another package contained a driver's license that had belonged to one of his victims. A Post Toasties box left by the roadside last month -- a "B" and a "K" scrawled above and below the "T" -- contained jewelry that authorities said might have belonged to other victims.
(BTK's habit of collecting souvenirs from his victims led some investigators to suspect he was single because they thought he would be unlikely to keep macabre trophies in a home where a wife or children could stumble across them.)
The flurry of recent communications from BTK captivated armchair detectives who noodled over every aspect of the case in Internet chat rooms. (Police paid close enough attention to the chatter that they subpoenaed information about several frequent contributors.) But even as the clues fascinated, they also frustrated, leaving many here wondering why police could not nab a killer who was dropping hints so brazenly. It seemed almost as though he wanted to be caught.
