The Secret Service suspended six people without pay after the assassination attempt on President Donald Trump last July, an official with the agency told NBC News.

Following an investigation into the assassination attempt in Butler, Pennsylvania, in which a gunman’s bullet grazed Trump’s ear, the agency issued the suspensions, which included both people in supervisory roles and line-level agents. The suspensions ranged from 10 to 42 days without pay. It is unclear when the agents were formally suspended.

NBC News has reported that multiple Secret Service officials were placed on leave for their actions before and after the assassination attempt. They included the special agent in charge of the Pittsburgh field office, which was tasked with coordinating security with local law enforcement ahead of the rally.

Almost immediately after the assassination attempt, lawmakers of both parties questioned the security failures that gave a 20-year-old gunman the opportunity to target and shoot Trump and kill firefighter Corey Comperatore, in what federal officials called an act of potential domestic terrorism.

Less than two weeks after the incident, Kimberly Cheatle stepped down as director of the Secret Service amid bipartisan calls for her resignation. At the time, she said she took “full responsibility for the security lapse.”

In an interview with ABC News before she resigned, Cheatle said there was a “short period” of time between when the gunman was initially flagged as suspicious and when he began shooting. A Senate briefing later revealed that Secret Service agents first spotted the gunman on a rooftop 10 minutes before Trump took the stage and 20 minutes before he opened fire. Secret Service personnel also faced criticism for how long it took to remove Trump from the stage after he was shot.

In December, a House task force investigating the incident made nearly a dozen recommendations for the Secret Service, including recording all radio transmissions and logs and creating new roles “for high-pressure moments.” In a 180-page report, the task force determined that the Butler shooting was “preventable” but concluded there was not a “singular moment or decision” by the Secret Service that enabled the gunman to “nearly assassinate” Trump.

The House investigation, however, praised the response of the Secret Service to the second assassination attempt on Trump in September in West Palm Beach, Florida, crediting it for demonstrating “how properly executed protective measures can foil an attempted assassination.”