The Unabomber's brother turned him in. Then spent 27 years trying to win him back

It was May 1996, and David Kaczynski, a counselor for troubled youth in upstate New York, sat down to write a letter to his brother Ted. A month earlier, his brother had been shockingly unmasked as the shadowy Unabomber, responsible for a 17-year campaign of bombings that had killed and maimed people across the country.Ted Kaczynski, a brilliant but mentally troubled mathematician who had retreated years earlier to a remote hovel in Montana, had been arrested based on information from a tipster