first letters. i was surprised i put it out there. i think it was just, bind, torture, kill, and then i had a label on me. like the green river killer, son of sam, a whole slew of others. the boston strangler. >> the police now knew the murders of the otero family and kathy bright were linked. but they had a serial killer in their midst. for tactical reasons, it would be several years before they disclosed the information to the public. still, they wanted to communicate with the mysterious strangler. police quietly placed a classified ad in the big hometown daily, btk, help is available. there was no response. and rader did not kill again for three years. >> it wasn't something i could do all the time. whenever it was convenient. it would have been easier, probably, if you were like a spy or somewhere where you could go sit there and watch. but i didn't have that. i had to work under camouflage. >> then in march 1977, rader