(NewsNation) — The U.S. Secret Service is facing questions about its resources and decision-making leading up to Saturday’s assassination attempt on former President Donald Trump.

As the Republican National Convention (RNC) unfolds Monday, lawmakers are calling on top law officials to testify about the Pennsylvania shooting that injured the former president, killed a spectator and critically hurt two more civilians.

“Obviously, the Secret Service men and women who were on the ground did the best job that they could, but I think the questions many of us have are for the leadership of the Secret Service,” said Rep. Anthony D’Esposito, R-N.Y. “Were there enough resources provided to that event? What’s the communication problem?”

Secret Service and Trump’s attempted assassination

President Joe Biden told the Secret Service to review “all security measures” for the Republican National Convention (RNC) in Milwaukee. The party’s nominating forum began Monday and is scheduled to end Thursday.

Biden said he spoke with Trump after the shooting and has since emphasized unity across political parties.

“Unity is the most elusive goal of all, but nothing is more important than that right now,” Biden said Sunday. “We’ll debate and we’ll disagree, that’s not going to change, but we’re going to not lose sight of the fact of who we are as Americans.”

Some attendees have said they spotted and tried to draw attention to the gunman before he opened fire. The situation remains under investigation.

The shooter reportedly fired from a rooftop 140 yards (420 feet) from the stage. That’s about 60 feet longer than an NFL-regulation football field. Homeland Security Secretary Alejandro Mayorkas said a direct line of sight like the one the shooter had Saturday “should not occur,” the Associated Press reported.

An officer from the local sheriff’s department climbed to the roof where the gunman was positioned, Butler County Sheriff Michael Slupe told the Associated Press. The shooter saw the officer and turned toward him before the officer dropped to the ground for safety and climbed down the ladder. The gunman then fired a shot at the former president, prompting Secret Service snipers to fire back, according to two officials who spoke to the AP on the condition of anonymity.

Former Buffalo Township Volunteer Fire Company Chief Corey Comperatore was shot and killed while attending the rally as a spectator. It’s unknown who fired the shot that killed Comperatore.

NewsNation emailed the Secret Service for that information as well as additional details about security decisions that day and plans moving forward. The agency had not responded as of Monday afternoon.

Two other spectators were wounded: David Dutch, 57, of New Kensington, and James Copenhaver, 74, of Moon. They were in stable condition Sunday at a Pittsburgh hospital, according to local police. More specific details about their conditions were not immediately available.

Who gets Secret Service protection?

The Secret Service announced changes to Trump’s protection as former president and a major party candidate. As of Monday, Trump had nearly the same coverage as Biden, a source told NewsNation reporter Kellie Meyer.

By law, the Secret Service is authorized to protect the president, vice president, president-elect and vice president-elect and their immediate families.

Independent candidate Robert F. Kennedy Jr. received Secret Security protection Monday. Both Trump and Biden pushed for the change in light of the suspected assassination attempt on the former president.  

Kennedy said last year his request for Secret Service protection was denied. It was the 1968 assassination of Kennedy’s father, Sen. and former Attorney General Robert F. Kennedy, that led to Secret Service protection for major candidates and their spouses.

Ohio Sen. J.D. Vance, who has been named Trump’s running mate, will get Secret Service protection as well.

Who decides who gets Secret Service protection?

Generally speaking, the U.S. Secret Service protects “major” presidential and vice presidential candidates. Who qualifies as a “major” candidate can vary.

The Secretary of the U.S. Department of Homeland Security makes that determination after talking with the Congressional Advisory Committee, comprised of the speaker of the House, the House minority leader, the Senate majority leader, the Senate minority leader and one additional member selected by the others.

According to the Secret Service website, factors taken under consideration during that process include:

• Threat assessments looking, in part, for explicit threats of bodily harm to a candidate
• Whether established national polls show a candidate polling at 15% or more for 30 consecutive days
• Whether the candidate is the formal or de facto nominee of a major party for president or vice president
• Whether an independent or third-party candidate polls at 20% or more of the RealClearPolitics National Average for 30 consecutive days

What is the Secret Service planning for the RNC?

Since the shooting, U.S. Secret Service Director Kimberly Cheatle has been in constant contact with Secret Service personnel in Pennsylvania, where agents worked to maintain the crime scene until the FBI arrived to take over the investigation, Cheatle said in an official statement Monday.

She’s also coordinating with Trump’s protective detail.

“In addition to the additional security enhancements we provided former President Trump’s detail in June, we have also implemented changes to his security detail since Saturday to ensure his continued protection for the convention and the remainder of the campaign,” she said.

Cheatle is scheduled to go before the House oversight committee on July 22.

Meanwhile, Trump is expected to attend the RNC for the next four days. The former president told the Washington Examiner that he intends to change the tone of his anticipated nomination acceptance speech.

“This is a chance to bring the whole country, even the whole world, together,” Trump said. “The speech will be a lot different, a lot different than it would’ve been two days ago.”

Police officers and vehicles were stationed in the security zone Monday near the Baird Center and Fiserv Forum and Pathern Arena in Milwaukee, where the RNC is taking place.

Milwaukee City bicycle cops were also present outside the secure zone Monday morning.

What’s the difference between presidential, former presidential and candidate protections?

The president and vice president receive protection for themselves and their immediate families. When the president travels, Secret Service agents work with the destination city, state and local law enforcement and public safety officials to make sure proper security measures are in place.

Former presidents and their spouses also receive protection for life unless they decline. The children of former presidents also receive Secret Service protection until they are 16.

Major presidential and vice presidential candidates and their spouses can receive protection within 120 days of a general presidential election.

What are the requirements to become a Secret Service special agent?

Not all special agents work directly with the president. Agents typically begin in an office before receiving their first protective assignment and later may be stationed out of a headquarters, according to the agency’s website.

During the first year with the service, special agent trainees receive several months of classroom, fitness, firearms and simulation training.

Agents must be U.S. citizens who are at least 21 years old when they apply and younger than 37 when they receive a conditional job offer. The latter age cap increases to 40 years old for some veteran applicants.

To qualify, applicants must not have any visible body markings, including but not limited to tattoos, on their head, face, neck, hands or fingers or any area below their wrist bone.

A “top secret” security clearance requirement means they must undergo a complete background investigation, including in-depth interviews, drug screening, credit check, medical exam and polygraph exam.

As for the more hands-on aspects of the job, agents are expected to be in  “excellent health and physical condition,” the website states. Applicants must have uncorrected vision no worse than 20/100 in both eyes. Any hearing loss must not exceed 25 decibels in either ear. They must also pass a physical test, written exam and drug test as part of the application process.  

Once employed, agents are required to attend ongoing training throughout their careers. That includes, in part, regular firearms requalification, emergency medicine courses and crisis training simulations.

NewsNation Digital Managing Editor Tulsi Kamath and Washington Bureau Chief Mike Viqueira contributed to this report from the RNC in Milwaukee.