because we had failed to act. we'd have blood on our hands. >> it took linda two months, but she finally convinced david to contact the fbi. >> there was no turning back, but i can't tell you how painful it was to just put my finger down and say, yes, he lives here, realizing that i could be sending my own brother to his death. when ted was arrested, under the bed where he slept was another bomb wrapped in a package apparently ready to be mailed to someone. >> ted kaczynski rejected his attorney's insanity defense and pleaded guilty to murder. he was sentenced to life in prison with no opportunity for parole. but to this day, david believes ted is insane and should be in a mental institution. >> my biggest regret was not to have clearer insight about ted's illness, that he was ill. >> david continues to write to