Former President Donald Trump was whisked off the stage at a rally in Butler, Pennsylvania, on Saturday night after a shooting that killed at least one rally attendee. The former president said he was "shot with a bullet" that pierced part of his ear.

The FBI early Sunday identified the suspected shooter as Thomas Matthew Crooks, 20, of Bethel Park, Pa. He was killed by the United States Secret Service.

"The FBI has identified Thomas Matthew Crooks, 20, of Bethel Park, Pennsylvania, as the subject involved in the assassination attempt of former President Donald Trump on July 13, in Butler, Pennsylvania," the FBI said in a statement, asking for anyone with more information to come forward.

Law enforcement officials told Spectrum News on Sunday that explosive devices were found inside Crooks' vehicle. Two law enforcement officials told The Associated Press there were also bomb-making materials found at his home.

Not much is known about the suspect, save for that he was registered as a Republican voter in Pennsylvania. He did, however, donate $15 to a progressive political action committee on the day of President Joe Biden's inauguration on Jan. 20, 2021, according Federal Election Commission records.

Early on in his speech, Trump was showing off a chart of border crossing numbers when banging sounds started ringing through the crowd. Someone could be heard saying "get down, get down" and directing Trump to the ground. The ex-president could be seen reaching with his right hand toward his neck. There appeared to be blood on his face.

He quickly ducked behind the podium as agents from his protective detail rushed the stage and screams rang out from the crowd. The bangs continued as agents tended to him on stage. Trump could be heard on microphones asking about his shoes.

The crowd cheered as he got back up and pumped his fist. Police began vacating the fairgrounds shortly after Trump left the stage.

Officials said that one spectator was killed, and two others were wounded, but were in stable condition as of Sunday afternoon.

Pennsylvania Gov. Josh Shapiro announced Sunday the man who was killed was Corey Comperatore, saying he was a former fire chief from the area who loved his family.

“Corey died a hero. Corey dove on his family to protect them last night,” the governor said.

The two wounded victims were identified by Pennsylvania State Police as 57-year-old David Dutch, of New Kensington, Pa., and 74-year-old James Copenhaver, of Moon Township, Pa.

According to a spokesperson for the Secret Service, a suspected shooter "fired multiple shots toward the stage from an elevated position outside of the rally venue." 

Secret Service spokesperson Anthony Guglielmi said that agents "neutralized" the suspected shooter and took protective measures to secure scene and get the former president to safety.

"The incident is currently under investigation and the Secret Service has formally notified the Federal Bureau of Investigation," Guglielmi added. The FBI said later Saturday that assumed the lead in the investigation into the incident.

A source told The Associated Press that an AR-style rifle was recovered by law enforcement at the scene of the shooting. Investigators believe the weapon Crooks used was purchased by his father at least six months ago, law enforcement officials told the Associated Press. Federal agents were still working to understand when and how his son obtained the gun and to gather additional information about Crooks, according to the officials.

In a statement on his Truth Social platform on Saturday night, Trump thanked the Secret Service and law enforcement for their "rapid response" and expressed his condolences to the family of the person who was killed at the rally, as well as his thoughts for another person who was "badly injured."

"It is incredible that such an act can take place in our Country," Trump said. "Nothing is known at this time about the shooter, who is now dead. I was shot with a bullet that 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," he added. "Much bleeding took place, so I realized then what was happening. GOD BLESS AMERICA!"

Trump traveled back to his New Jersey golf club to spend the night. His campaign and the Republican National Committee said in a statement Saturday night that the Republican National Convention will continue as planned in Milwaukee next week. Trump said on Sunday he would fly to Milwaukee in the afternoon.

"Based on yesterday's terrible events, I was going to delay my trip to Wisconsin, and the Republican National Convention, by two days," Trump wrote on social media. "But [I] have just decided that I cannot allow a 'shooter,' or potential assassin, to force change to scheduling, or anything else."

In remarks from the White House on Sunday after being briefed by the nation's top law enforcement officials, President Joe Biden said he had a "short but good conversation" with Trump on Saturday evening and ordered an independent review of the security measures at the rally and the upcoming Republican National Convention. 

"We must unite as one nation," he said. "We must unite as one nation to demonstrate who we are."

In previous remarks on Saturday evening, Biden said "there’s no place in America for this kind of violence" and called the shooting "sick."

Shortly after the shooting, Biden's reelection campaign said it was putting a hold on "all outbound communications and working to pull down our television ads as quickly as possible.” It was not clear how long the suspension would last.

Biden also cancelled a planned trip to Texas to mark the 60th anniversary of the Civil Rights Act. The White House said he would again address the nation at 8 p.m. ET on Sunday.

Amid prayers for Trump and condemnations for political violence from world leaders and politicians on both sides of the aisle, some of his congressional allies called for investigations. House Speaker Mike Johnson, R-La., said on NBC News' "Today" on Sunday that Congress would launch a full investigation and that he spoke with Mayorkas on Saturday night and "asked him some pointed questions."

"Political violence in all forms is unamerican and unacceptable," House Oversight Chairman James Comer said in a statement. "There are many questions and Americans demand answers. I have already contacted the Secret Service for a briefing and am also calling on Secret Service Director Kimberly Cheatle to appear for a hearing. The Oversight Committee will send a formal invitation soon."

One Republican lawmaker, Rep. Mike Collins of Georgia, even went as far as to say that Biden "sent the orders," referencing comments reportedly made by the Democrat about putting Trump "in a bullseye" in terms of a campaign strategy. 

Ohio Sen. JD Vance, a possible Trump running mate contender, also condemned rhetoric from Biden and Democrats and directly blamed them for the incident.

"Today is not just some isolated incident. The central premise of the Biden campaign is that President Donald Trump is an authoritarian fascist who must be stopped at all costs," Vance charged. "That rhetoric led directly to President Trump's attempted assassination."

This is a developing story. Check back later for updates.

The Associated Press contributed to this report.