A why-it-happened account of a double killing, with a clear murderer-as-victim slant that will generate strong pro/con reactions. In September 1969, Geoffrey King, 17 and zonked on acid, stabbed to death his mother and grandmother at their Palos Verdes home, then stabbed himself in the chest 13 times--and miraculously survived. Convicted of voluntary manslaughter but acquitted by reason of insanity, Geoffrey spent only three years in mental institutions before being set free, at age 21, to put his life back together.