A former Secret Service agent said counter-snipers at the Pennsylvania rally where a would-be assassin wounded former President Donald Trump should have had "360-degree coverage" of the event and surrounding buildings.
"I don't know how many they had, but they usually always look for 360-degree coverage," former Secret Service agent Anthony Cangelosi told Business Insider. "So that's one thing that's going to be considered."
The Federal Bureau of Investigation identified the shooter as a 20-year-old man from Bethel Park, Pennsylvania.
Cangelosi, who is now an adjunct professor at the John Jay School of Criminal Justice at the City University of New York, said the primary question law enforcement would likely be asking is how the suspect could have made it to the top of a nearby building undetected.
Butler Township Sheriff Michael Slupe told The Washington Post that a local officer encountered the suspect before the shooting but dropped to the ground because he did not have his weapon.
For a large event where the president or former president is speaking, the Secret Service on the scene would typically work with law enforcement to design a "site plan" with a mock-up of the event space and all surrounding buildings, Cangelosi said.
This plan will be paramount for investigators in determining what possible failures occurred during the rally, according to Cangelosi.
"All the posts - meaning personnel, Secret Service or uniformed police officers, where they were positioned, what their duties were to secure that post, what considerations were given to the outer perimeter, in this case, the other building," will be included in the site plan, Cangelosi said.
Cangelosi said the Secret Service would sometimes use "counter-sniper response units," which are posted on the ground and can quickly move into position if they notice a threat.
"However, time could also be of the essence, right?" Cangelosi said. "You might not have the ability to send a counter-sniper response team up to the location"Snipers often quickly have to make a decision when they notice a potential threat like an open window or a person sitting on a roof Cangelosi said.
"What if you find out, 'Oh, I just killed a kid, 20-year-old kid who loves the protected, and he couldn't get in the venue, and he just wanted to get up on that roof,'" Cangelosi added. "No one wants to be in that position."
Cangelosi said he expects the Secret Service to amp up security at future events moving forward. Trump has already confirmed he plans to speak at the Republican National Convention in Wisconsin next week.
"The Secret Service is well aware of the fact that they have to be perfect all of the time," Cangelosi said. "And the one time you're not, it's going to bring an increased scrutiny."