nothing ever to hint at that that something could be amiss with my father. >> paula was a member of dennis rader's. >> my dad and my mom met in the fall of 1970. >> rader's mother knew her and knew that dennis was coming home from the military. and she wanted paula to meet him. >> he had just got back from the air force. they started dating. they got married nine months later in may of '71. >> i think he fell in love, and they were two good christian kids who wanted to get married in the right way, so there was nothing unusual about it. >> when dennis marries paula, she obviously has no idea that dennis has already been having fantasies, and maybe even obsessions about harming other people, killing other people, tying them up, et cetera. >> he's already looking inside people's houses. he's stalking people. he's already breaking into people's homes. he's already living a double life. >> he knew before he met my mom what he was probably capable of. >> reporter: you think he knew then? >> well, yeah. i mean, why did he get married? was it because he didn't want to be that other person or did you just

here again, deborah roberts. >> btk is arrested. >> police say this man, 59-year-old dennis rader, isfter 30 years, the btk killer who terrorized the city of wichita, kansas, was finally in custody. >> we have learned that rader has been charged with ten counts now of first-degree murder. >> reporter: the community in shock. dennis rader was a serial killer in plain sight. >> dennis rader is literally the least likely suspect. he is a pillar of the community. he's the president of his lutheran church congregation. he is a compliance officer. he wore a badge. >> reporter: it was daughter kerri who unwittingly and inadvertently helped officials make the arrest. >> they got a warrant for my medical records at the college health center. >> you had no idea? >> i had no idea. they found i had annual pap smears, they had a sample of my dna. >> in some ways your dna sealed your dad's fate. >> it did, but nobody told me this. it would have been nice if someone had asked me for my dna. i would have willingly given it. it felt like invasion of my privacy. >> he didn't think they had kept biologi