![Col. Christopher L. Paris.](https://media.necn.com/2024/07/GettyImages-2163254383_b242fc.jpg?quality=85&strip=all&crop=0px%2C13px%2C1024px%2C576px&resize=320%2C180)
The gunman who tried to assassinate former President Donald Trump was identified as suspicious before the shooting because he was hanging around but never attempted to enter the July 13 campaign rally and that suspicion was later heightened when he was seen with a rangefinder, the commissioner of the Pennsylvania State Police testified Tuesday.
Thomas Crooks, 20, first became suspicious because he “was milling about and he stood out to them because he never made his way to a point of ingress to the venue,” Pennsylvania State Police Col. Christopher Paris said at a House Homeland Security Committee hearing.
The suspicion grew when Crooks was later seen with a range-finder, a device that measures the distance from a target.
In his testimony, Paris said that in his briefings he was told that in addition to Crooks, three other people had been identified as suspicious.
Paris said the Butler County Emergency Services Unit (ESU), which was tasked with securing the building where Crooks fired from, relayed the suspicion and a photo of Crooks to the state police, which then passed along the message to the Secret Service.
Officers with the Butler County ESU spotted Crooks from a second-story window and left their post to search for him, Paris said, adding that he cannot give an exact timeline.
U.S. & World
Crooks was not designated as an actual threat until seconds before he opened fire, Paris said. The gunfire struck Trump in the ear, killed one rallygoer and wounded another.
Paris said one of his area commanders specifically asked the Secret Service about a plan to secure the building during a final security planning walk-through two days before the shooting.
“We were told Butler ESU was responsible for that area by several Secret Service agents,” Paris said.
The Pennsylvania State Police’s role was to support the Secret Service at Trump’s presidential campaign rally in Butler, Pennsylvania, Paris said.
U.S. Secret Service Director Kimberly Cheatle stepped down from her position Tuesday after widespread calls from lawmakers for her to resign following the assassination attempt on Trump, three sources told NBC News.
Her resignation comes just one day after lawmakers grilled her at a House Oversight Committee hearing where she did not provide clear answers when asked about whether the Secret Service had secured the building the gunman fired from and how he gained access to the roof.
The Pennsylvania State Police provided 32 members, Paris said, adding that their two main jobs were to help transport Trump and secure posts inside the perimeter. He said the Pennsylvania State Police also provided two marked cars with uniformed troopers outside of the security perimeter to “provide roving duties.”
The agency is investigating the shooting and has interviewed 100 people and gathered 1,000 pieces of evidence in the process, Paris said.
This story first appeared on NBCNews.com. More from NBC News: