Trump assassination attempt: 'Fundamental security failure' allowed gunman to open fire at presidential campaign rally, experts say

Open campaign events, such as Saturday's, are tough to secure against all threats, but insiders said they were surprised that the gunman was able to scale a roof overlooking the rally in Butler, Pennsylvania, where Donald Trump was speaking.

Security experts familiar with the demands of keeping politicians safe have said "a fundamental security failure" occurred as a gunman was able to get close enough to Donald Trump to shoot him at a presidential campaign rally.

Thomas Matthew Crooks, 20, fired several rounds at the former president as he gave a speech to supporters in Butler, Pennsylvania, on Saturday, before being shot and killed by secret service agents.

Mr Trump was hit in the ear in the assassination attempt, but is "fine", his campaign said, while one spectator was killed and two others were injured.

Steve Nottingham, who has helped provide security for visiting world leaders, including presidents, told NBC, Sky's US partner, it was "a fundamental security failure".

The former Special Weapons and Tactics (SWAT) team commander, suggested pre-event research and real-time monitoring of places a gunman could shoot from had broken down.

He said: "They were behind the curve, because they should have had those places covered ahead of time."

His comments come after the BBC interviewed a man who described himself as an eyewitness, who said he saw a man armed with a rifle crawling up a roof near the event. The person, who the BBC did not name said he and people he was with started trying to alert security, pointing at the man.

Retired Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) agent Jim Cavanaugh said he was surprised that the gunman was able to occupy a raised position within rifle range of the rally site.

Mr Cavanaugh said: "Whenever I've been with them, every single high ground is taken by them or the local SWAT police. There's nobody allowed walking on rooftops. They command the high ground."

He said a high-powered rifle like an AR-15 can hit targets 600 feet (182m) away and Mr Trump was about 444 feet (135m) from the rooftop where the shooter was found dead, NBC News said, based on an analysis of Google Earth images.

Mr Cavanaugh said: "Having been on Secret Service details, it's amazing to me that somebody was on an elevated position that they didn't know about."

But Pennsylvania State Police Lieutenant Colonel George Bivens defended those in charge of security, calling it "incredibly difficult to have a venue open to the public and to secure that against any possible threat against a very determined attacker. That's a huge lift".

The Secret Service did not immediately respond to a request for comment, NBC said.

FBI special agent Kevin Rojek told reporters law enforcement was not aware there was a man on the rooftop until he started firing and said it was "surprising" how many shots the gunman managed to fire.

Trump supporters in the front row of the rally heard a series of pops and saw secret service agents jump on the stage as Mr Trump, the presumptive Republican candidate in November's presidential election, ducked.

Mr Trump said in a post on his Truth Social site a couple of hours later that a bullet "pierced the upper part of my right ear.

"I knew immediately that something was wrong in that I heard a whizzing sound, shots, and immediately felt the bullet ripping through the skin. Much bleeding took place, so I realised then what was happening."

Former Secret Service agent Evy Poumpouras, who has protected multiple presidents, including Barack Obama and George W Bush, said it is impossible to eliminate every potential threat at a rally.

She said: "Somebody can be out in the distance and really engage your target from a long range, and there are weapons out there that allow you to do this.

"Let's say you hunkered [locked] this whole area down. You've got the magnetometers (instrument used for measuring magnetic forces); you've got the tactical element. Everything is locked and tight. How do you secure that outer perimeter? How far do you go? And can you cover everything? That's a problem.

"Even if somebody is in an elevated position or not, how do you secure all of those elevated positions when you have weapons with the capabilities that are able to shoot long distances? This is what you are up against."

Former New York City police officer Jillian Snider said it is routine for law enforcement to do a perimeter check extending a few hundred yards ahead of such an event.

"That doesn't mean that someone can't sneakily make their way to one of those positions afterward, especially if it was someone who had done some preplanning. There are a lot of places in that area to hide, and you can't monitor every possible position.

"Someone who is that driven to do something like this will find a way to try and get the job done."