the opposite. >> he felt invincible, unstoppable. and that's why many serial killers communicate with the police. not because they want to invite capture, because they feel that the police are no match for their skill, their countrying. their stardom. their brilliance. so what often happens with most serial killers is they get so cocky and they make a mistake. >> and that's just what happened, it was rader, himself, who helped bring police to his door. it started in january, 2005, when rader placed a letter in a pick-up truck at this home depot, which eventually made its way to police. in it, rader identifying himself only as btk asked the police whether they could catch him if he used a computer disc to communicate. he asked the police to respond in a classified ad and he asked them too be honest. >> he actually asked the police -- >> they said no. >> did you really think they were going to tell you the