ian gibson , 55 , was a lauded figure among u.s. safari enthusiasts , who would commission him to slaughter prized animals near his home in south africa .
on wednesday , he was tentatively approaching the young bull elephant in zimbabwe 's zambezi valley when the animal charged , and knelt on gibson until he died .
crushed to death : ian gibson , 55 , was killed by a young bull elephant while measuring its ivory for a u.s. client .