WASHINGTON (NEXSTAR) – The FBI is leading the investigation into how a gunman could have gotten close enough to try to assassinate former President Donald Trump.

While that question remains, federal officials announced Monday security is increasing across the board. 

“Our entire administration is grateful that former President Trump is ok,” Homeland Security Secretary Alejandro Mayorkas said during Monday’s White House press briefing. “Maintaining the safety and security of the president, the former president and their campaign events is one of our most vital priorities.”

Mayorkas said Trump and President Joe Biden are the subjects of constant threats.

“We are in a heightened and very dynamic threat environment,” he said. 

Mayorkas said he is also working to select the person who will lead an independent review into Trump’s attempted assassination. President Biden requested it, and the findings will be made public.

“So that the American people have confidence,” he said.

Mayorkas would not answer questions about security at Saturday’s shooting in Pennsylvania, but some local officials released new information.

Butler Township Manager Tom Knights said one of his officers was lifted up by another officer to the roof where the shooter was, after hearing from the crowd about a suspicious person. 

“Shooter turned, rifle was pointed at the officer,” Knights said. “Officer, defensive move, kind of ducked, fell, lost his grip on the building. Did fall to the ground. Probably an eight-foot fall, somewhere in that vicinity. Did sustain an ankle injury.”

Officials said moments later, the gunman started shooting.

“I think all law enforcement on site did everything that they could,” said Butler County Sheriff Michael Slupe. 

Slupe urged the public to hold off on jumping to conclusions.

“I hope they’re not made a scapegoat because they did their job to the best of their abilities,” he said.

Mayorkas also announced Monday that independent candidate RFK Jr. will now receive Secret Service protection following President Biden’s request.