US Secret Service Director Kimberly Cheatle resigned on Tuesday after the agency came under harsh scrutiny for its failure to stop a would-be assassin from wounding former President Donald Trump during a campaign rally, according to media reports.

The US Secret Service is investigating how a gunman armed with an AR-style rifle was able to get close enough to shoot and injure former President Donald Trump at a rally Saturday in Pennsylvania, a monumental failure of one of the agency’s core duties.