NEW : Jared Loughner 's parents took away his shotgun and told him he needed help . NEW : Loughner bought six or seven boxes of ammunition , documents show . Loughner , 24 , is serving a life sentence without the possibility of parole after pleading guilty last year to 19 charges in exchange for the government not seeking the death penalty . NEW : The FBI has been investigating the shooting for months. NEW : Loughner ran from parents just before the shooting rampage , mom says .
NEW : Jared Loughner 's parents took away his shotgun and told him he needed help . NEW : Loughner bought six or seven boxes of ammunition , documents show . NEW : The FBI has been investigating the shooting for months. NEW : Loughner ran from parents just before the shooting rampage , mom says .