The Secret Service is being held to an impossible standard, says a former royal bodyguard

Simon Morgan, a security expert who worked for the royal family, has defended Donald Trump's Secret Service agents following the shooting last week.

• Security expert Simon Morgan spoke to BI about the assassination attempt on Donald Trump. 
• Morgan praised the Secret Service's response but welcomed an investigation into the attack. 
• The FBI has interviewed 100 law enforcement agents and witnesses.

The US is still reeling from the assassination attempt on Donald Trump more than a week ago.

The former president praised the Secret Service agents who piled in when a gunman opened fire at an election rally in Butler, Pennsylvania.

It's a completely different response to the commentators, security experts, and ordinary observers who questioned why officials weren't able to prevent the attack from taking place at all.

Simon Morgan, a security expert and former bodyguard to the British royal family, said the criticism of the Secret Service hasn't been entirely fair.

Morgan worked as a protection officer at Buckingham Palace from 2007 until 2013 and now runs the private security firm Trojan Consultancy.

Speaking to Business Insider, Morgan said the Secret Service agents "did exactly what they should have done" because they "ran towards danger" and used their bodies to cover the former president.

Trump's ear was pierced by a bullet, and a rallygoer was killed while shielding his family from the bullets. Just moments later, a Secret Service sniper shot and killed the gunman.

"They took him out with one shot right between the eyes," Trump said in an interview with the New York Post.

"They did a fantastic job," he said. "It's surreal for all of us."

Secret Service agents were unfairly judged, Morgan said

Morgan cautioned members of the public with "limited knowledge" to think twice before commenting.

"The only people who can comment on what happened are those Secret Service agents," Morgan said.

"We do have keyboard warriors who play 'Call of Duty' saying, 'I would have done this,'" he said.

Nonethless, Morgan acknowledged that an investigation into how the shooter wasn't challenged before the attack will be beneficial.

The FBI announced last week that it had launched an investigation into the assassination attempt. Around 100 law enforcement agents, event attendees, and witnesses have already been interviewed, according to a statement on the FBI's website.

CBS News reported that Pennsylvania State Police notified the Secret Service about a suspicious individual with a rangefinder around 20 minutes before the attack. But according to a local law enforcement officer and the Butler County sheriff, law enforcement weren't aware that he also had a gun.

At least one bystander also described attempts to warn law enforcement after spotting the shooter.

"If you don't learn from history, you're failing to learn," Morgan said.

Morgan praised Trump's swift reaction to the shooting

After the first shot was fired, the former president ducked his head before agents forced him further to the ground.

Morgan said that even though Secret Service agents would have prepared Trump for emergency scenarios, "you never quite know what people are going to do" when it's real.

"He could have run away. And then you've got a scenario where the Secret Service are chasing after him," Morgan said. "He could have just stood there and not done anything and frozen, and made himself an easy target."

As the agents tried to steer Trump away from the scene, he stopped briefly to raise a defiant fist in the air. The photo made waves around the world, but the former president was undoubtedly risking his life to get it.

"Only he could answer why he did that," Morgan said.

"It may be the euphoria, of 'Actually I'm still alive.' It might be, 'I've got to celebrate that, and show to the outside world that I'm still alive,'" he added.

"A lot of people say it's the most iconic photo they've ever seen," Trump told the New York Post.

"They're right, and I didn't die. Usually, you have to die to have an iconic picture."