At a recent Trump rally in Pennsylvania, chaos erupted when an armed man, Thomas Matthew Crooks, opened fire from a nearby roof, leading to tragic injuries and a death. Despite reports of his suspicious behavior before the event, security failed to stop him from getting dangerously close to Trump. New details have emerged that a police officer encountered the gunman on the roof before the shooting. As investigators piece together how this happened, shocking revelations about the Secret Service’s shortcomings are emerging, raising questions about the safety measures in place for high-profile events.

Minutes before gunfire broke out at Donald Trump’s Pennsylvania rally, there were warning signs of trouble: authorities received a tip of a suspicious individual walking close to the magnetometers and appeared to be swapping pictures of the man. On an adjacent roof, witnesses pointed and yelled at an armed man.

The gunman turned and aimed his rifle at the policeman who had scaled the roof to look around. However, the policeman was unable to fire a single shot reports AP News.

After firing an AR-style weapon toward the former president, 20-year-old Thomas Matthew Crooks was quickly taken down by a sniper, but it was too late. Investigators are currently working feverishly to figure together how an armed civilian with no military experience gained an advantage against groups of Secret Service agents by reaching the high ground.

Former police chief and event security coordinator for two previous presidents Stan Kephart claimed that the shooting came after “an absolute and abysmal failure” on the part of the Secret Service to safeguard Trump. He said that in the end, the agency bears responsibility for the candidate’s security.

“You don’t get to blame other people. They are under your control,” said Kephart, now a consulting expert on law enforcement event security.

An impartial probe into the attempted assassination has been authorized by President Joe Biden. Alejandro Mayorkas, the secretary of homeland security, acknowledged that the gunman never should have been at that dangerous location but yet expressed ” full confidence” in the leadership of the Secret Service.

“We are speaking of a failure,” Mayorkas told CNN. “We are going to analyze through an independent review how that occurred, why it occurred, and make recommendations and findings to make sure it doesn’t happen again.”

The Pennsylvania State Police and the Secret Service were receiving security assistance for the rally from at least a dozen police officers and sheriff’s deputies.

According to an anonymous law enforcement official who was not allowed to discuss the case, several rallygoers reported to local cops that Crooks was acting suspiciously and pacing near the magnetometers.

Before the incident, a Butler Township police officer had come into contact with the shooter on the roof. According to local officials, the police were searching for the suspicious individual when another officer lifted him so he could grip the edge of the roof.

According to Butler County Sheriff Michael Slupe, the gunman turned and pointed his rifle at the officer, who then slid back down to safety.

Slupe claimed the police could not have used his gun in the situation since he was inside the demonstration site when the shooting started and was not present when it happened.

“I think all law enforcement on site did everything that they could, especially the local law enforcement,” Slupe told The Associated Press on Monday. “I hope they’re not made a scapegoat, because they did their job to the best of their abilities.”

The officer lost his balance and was not backing away, according to Butler Township Manager Tom Knights, and fell eight feet (2.4 meters) to the ground.

“He was literally dangling from the edge of a building and took the defensive position he needed to at that time. He couldn’t hold himself up,” Knights said.

The ten-year police enforcement veteran, who was wearing a walking boot, had a serious ankle injury from the incident, according to Knights.

The gunfire seriously injured two bystanders. Corey Comperatore, a 50-year-old former fire chief, passed away.

The FBI stated that it was looking into the incident as a possible case of domestic terrorism, but it had not yet determined the attacker’s specific ideological motivation. The FBI thinks Crooks acted alone because the car he drove to the event contained ingredients for building bombs.

The FBI announced on Monday that analysts had successfully obtained access to the gunman’s phone. However, according to a law enforcement official speaking under anonymity who was not authorized to publicly discuss the case, the device has not provided any significant evidence regarding a possible motive.

Additionally, the official stated that detectives think Crooks bought 50 rounds of ammo on the day of the assault.

The FBI has received hundreds of tips from digital media and has interviewed law enforcement officers, rally participants, and other witnesses in close to 100 interviews.

Authorities said they think the gunman’s father bought the AR-style rifle. According to the FBI special agent in charge of Pittsburgh, Kevin Rojek, investigators are still unsure of whether Crooks grabbed the gun without his father’s consent.

Crooks’s location on the roof was approximately 147 yards (135 meters) away from Trump’s speaking position, a range that would allow a proficient marksman to hit a human-sized target. To be eligible to use the M-16 rifle recruits for the United States Army must hit a scaled human silhouette at that distance.

Former NYPD officer Patrick Brosnan, who now heads a nationwide private intelligence and security company that has guarded presidents, recommended that the building next to the stage be guarded and under observation right away. The effective range of a weapon similar to the AR-15 is around 400 to 500 yards (366 to 457 meters). Trump was less than 150 yards (137 meters) away from the gunman.

“It would just seem to me to be elemental and rudimentary as it relates to providing a steel band or circular band of protection for the former president, who is fully exposed,” said Brosnan, who has trained with the Secret Service and previously spoken with Trump and his family about security issues.

Explore exclusive GGI coverage of Donald Trump’s assassination attempt.