After the attempted assassination of Donald Trump in July, the U.S. Secret Service upped its security for him, officials say. But in the wake of an apparent second attempt on the former president's life, how that security detail works is coming under even more scrutiny. 

The FBI is investigating after a man pointed a high-powered rifle with a scope into Trump's golf club in West Palm Beach, Fla., on Sunday, while Trump was on the course. A suspect was arrested soon after. This comes just nine weeks after the Republican presidential nominee was wounded by a sniper at a Pennsylvania rally.

Who protects U.S. federal officials? 

There are several tiers of security detail for U.S. officials across the three branches of government, with different agencies responsible for different individuals. 

The State Department arranges protection for the Secretary of State, the Deputy Secretary of State and other official representatives of the U.S. government, and their family members, for example, while the U.S. Capitol Police protects members of Congress. 

But the highest level of security is provided by the Secret Service, which assigns protective details as directed by Homeland Security. By law, the Secret Service is tasked with protecting the U.S. president, the vice-president or whoever is next in command, the president- and vice-president-elect and their immediate families, as well as former presidents, their spouses and children up until the age of 16.

The protection of former presidents lasts their entire lifetime, but can be declined, which Richard Nixon did in 1985. 

The service also protects "major" presidential and vice-presidential candidates, as determined by the Secretary of Homeland Security, within 120 days of a general presidential election.

Other federal, state and local agencies may be called upon to assist. The Secret Service also protects other officials on a temporary basis, such as visiting heads of state. 

Because of the nature of the job, the exact operations of the Secret Service are generally kept under wraps, but agents are easily spotted escorting officials to and from events.

The Secret Service currently protects 36 people on a daily basis, the agency's then-director Kimberley Cheatle said in July. 

How much security did Trump have on Sunday?

Initially, officials indicated the level of security was appropriate for Trump's position. 

"He's not the sitting president, if he was we'd have the entire golf course surrounded," Sheriff Ric Bradshaw with the Palm Beach County Sheriff's Office told the media on Sunday. "But because he's not, security is limited."

WATCH | Rowe describes 'paradox' of operating a security detail:

'We have done more with less for decades,' acting Secret Service head says

U.S. Secret Service acting director Ronald Rowe says he 'ordered a paradigm shift' in the approach to protection following the attempted assassination of former U.S. president Donald Trump in Butler, Pa., in July — but says the current workload means 'we are red-lining' agents.

But on Monday, Secret Service acting director Ronald Rowe said Trump receives its "highest" level of security. 

The golf course was not checked in advance, he said, because agents didn't know Trump was heading there. 

"It was an off-the-record movement, meaning it was not on [Trump's] official schedule," he said. 

While golfing, Trump was accompanied by a security bubble of Secret Service agents, who would clear an area before he entered. An agent spotted a rifle poking out of the treeline and immediately fired. 

Rowe said that "the security plan worked" against the apparent attempt.

Former FBI agent Kenneth Gray told CBC's As it Happens that a golf course is much more difficult to secure than a political rally. 

At a rally, "you have people going through magnetometers, you have people checking bags, you have a lot of additional law enforcement that should secure the middle and outer perimeter," he said. 

At a golf course, "you have none of that."  

WATCH | Suspect taken into custody:

Bodycam video shows arrest of man charged in apparent Trump assassination attempt

Bodycam video released on Monday showed law enforcement taking a man into custody on Sunday in relation to the suspected assassination attempt of former U.S. president Donald Trump at his golf club.

Why is the FBI involved? 

Secret Service agents aren't police officers. While its agents can execute warrants and perform arrests as directed by Homeland Security, the task of investigating an incident like Sunday's falls to law enforcement.  

The FBI investigates all federal crimes not assigned to another agency including threats to national security.

Has security gone up since the first assassination attempt? 

According to Rowe, it has. Since July 13, the Secret Service "moved to increase assets," he said Monday. "Those things were in place yesterday."  

He also claimed that the level of security was comparable to when Trump was president. 

"For those of you that were here in 2017, when the president was in office, when you look at that [security] footprint now and you look at it today, there's not much difference there," he said.

WATCH | Biden reacts to news of apparent assassination attempt:

Biden says U.S. Secret Service ‘needs more help’

The FBI said Donald Trump was the target of an apparent assassination attempt at his golf club in West Palm Beach, Fla., on Sunday. This comes just nine weeks after the former U.S. president survived a previous attempt on his life.

How have previous shootings changed the Service?

The Secret Service was originally created to combat counterfeiters, and wasn't tasked with protecting the president until after the 1901 assassination of President William McKinley.  

A more recent turning point was the attempted assassination of Ronald Reagan in 1981, when the then-president was coming out of a Washington hotel. Gunman John Hinckley Jr. was standing in the crowd less than five meters away and fired several shots before agents tackled him. After that, presidents were driven into underground parking garages to enter buildings, and more security cover was implemented. 

The service was also criticized after a gunman shot at the White House in 2011 during the Obama presidency, smashing a second storey window. A report later found the Secret Service had failed to properly react to and investigate the incident. 

What happens now? 

House Speaker Mike Johnson said on Monday that the House will be demanding more Secret Service protection for Trump, saying he needs more attention than any other person.

U.S. President Joe Biden also stated Monday that the Secret Service "needs more help," and urged Congress to step up. He said he believed they may need more personnel. 

Rowe said on Monday that the shooting on July 13 showed him that the Secret Service needs a "paradigm shift."

"We need to get out of a reactive mindset and into a readiness mindset."