NEW : Grandmother died of loss of blood . Helicopter was on a reinforcement mission , a military official says . 22 of the dead are former Navy SEALs , U.S. officials say . A few belonged to the same unit that killed Osama bin Ali .
NEW : Grandmother talks of loss of SEAL . Helicopter was on a reinforcement mission , U.S. military official says . 22 of the dead are U.S. Navy SEALs , U.S. officials say . A majority belonged to the same unit that killed Osama bin Laden .