Thomas Matthew Crooks: What we know about the Trump attacker

The small Pittsburgh suburb of Bethel Park in Pennsylvania is reeling after the FBI named a young local man, Thomas Matthew Crooks, as the person who shot at Donald Trump during a campaign rally and shocked the nation.

Investigators believe that Crooks, armed with a semi-automatic AR-15 rifle, opened fire at the former president while he was addressing a crowd in Butler, Pennsylvania, leaving one audience member dead and two others wounded.

The 20-year-old kitchen worker was shot dead at the scene by a Secret Service sniper, officials said.

In his well-to-do hometown, however, neighbours are in shock, seemingly unable to grasp how a quiet young man is now accused in the shooting.

The FBI, for its part, has said only that Crooks was the "subject involved in the assassination attempt on the former president and that an active investigation was under way."