Trump's gunmen see going into position before pull the trigger

Donald Trump’s would-be assassin was filmed shuffling into position two minutes before he fired his shots at the presidential candidate.

One onlooker raised the alarm with police, but they failed to stop him before he opened fire, which has led to anger over security lapses at the rally in Butler, Pennsylvania.

Video footage posted online shows several people pointing at Thomas Crooks as they stood watching from the outer perimeter of the event, which was meant to be under the control of local police.