Remote patrol

Of all the troubled young teen-agers who went to their schools and opened fire on their classmates, none was more troubling than Kip Kinkel. With two loving parents who expressed their concern for him right up to their final moments, Kinkel's hardly seemed to be that of the bad seed planted in fertile ground. But "Frontline" (9 p.m., Channel 19) does a remarkably incisive job taking key episodes in Kinkel's life and piecing them into a coherent narrative. Watching it, we see Kinkel and his parents descending into a pit of mutual despair from which they tried desperately to escape, with counseling and Prozac and father-son bonding and birthday gifts like a 336 Marlin rifle. @ART CAPTION:Kinkel @ART:Photo (color)