Butler, Pennsylvania - A local police officer allegedly attempted to stop the gunman who shot and wounded former President Donald Trump during a recent campaign rally.

On Sunday, Butler County Sheriff Michael Slupe gave an interview with CNN, where he recalled how officers at the rally were alerted about the presence of a man on the roof of a building, but were not informed that he was armed.

Upon finding the gunman's location, Slupe claims one officer hoisted another officer up to climb onto the roof.

When the gunmen saw the officer at the roof's edge, he allegedly turned and pointed his weapon at him, causing the officer to let go, dropping below to "take cover."

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Moments later, the gunman, who has now been identified as 20-year-old Thomas Crooks, began opening fire, wounding Trump and two others, and killing one bystander before a Secret Service sniper fatally shot him.

The incident has sparked harsh criticisms aimed at the Secret Service, which some believe is at fault for safety vulnerabilities that allowed the shooting to take place.

When asked if he believed the security lapse that gave the shooter a direct line of sight to Trump was a failure, Slupe responded, "Obviously," adding that if he had known, he would have done "everything to stop [Trump] from coming out."