Live coverage: Trump rally shooting victims identified; Biden speaking again Sunday night

null - The shooting at former President Donald Trump's rally Saturday is being investigated as an attempted assassination. 

One spectator was killed and two others critically injured in the shooting at the rally in Butler, Pennsylvania.

Trump was also wounded but is "fine." In a statement posted to his Truth Social account, he called for unity and resilience as investigations into the shooter and his motives continued. 

The Federal Bureau of Investigations early Sunday identified the shooter as 20-year-old Thomas Matthew Crooks. Crooks was fatally shot by Secret Service agents following his alleged attempt to kill Trump. 

The FBI is investigating the shooting as possible domestic terrorism. 

Here's the latest details in the investigation (all estimated times are Eastern):

RELATED: Donald Trump bloodied but "fine" after shooting at rally, campaign says

9:45 p.m.

Former President Trump recently told an outlet that he has "completely" rewritten the speech that he planned to give at the Republican National Convention (RNC) in Milwaukee this week.

In a recent interview with the Washington Examiner's Salena Zito, Trump said that his new speech will focus on uniting Americans after Saturday's shocking events.

"The speech I was going to give on Thursday was going to be a humdinger," Trump said. "Had this not happened, this would’ve been one of the most incredible speeches...Honestly, it’s going to be a whole different speech now."

Instead of focusing on attacking President Biden's policies, his new speech will reportedly aim to bring the country together.

"This is a chance to bring the whole country, even the whole world, together," the former president explained. "The speech will be a lot different, a lot different than it would’ve been two days ago."

8 p.m.

President Joe Biden urged Americans to "lower the temperature in our politics" and condemned the assassination attempt of former President Donald Trump. 

"We must never descend into violence," he said. 

Biden also called for unity, saying that he will continue to push to preserve the country's democracy.  

6:45 p.m.

Trump Force One landed in Milwaukee at around 6:45 p.m. on Sunday evening, just a day after a man allegedly attempted to assassinate former President Trump in Butler, Pennsylvania.

Eric Trump shared a video of Trump Force One landing in Milwaukee from the cockpit of the aircraft on social media.

Another video shared by Dan Scavino Jr., a senior advisor to former President Trump, showed Trump's motorcade driving into Milwaukee

5:00 p.m.

The U.S. Secret Service said Sunday that local authorities were alerted to a threat ahead of the Trump Rally in Butler, Pennsylvania on Saturday, but could not find the gunman in time.

Local law enforcement was alerted to a suspicious individual by attendees but could not locate Mr. Crooks before he climbed onto the roof and opened fire, according to US Secret Service Spokesman Anthony Gugliemi.

Mr. Guglielmi tells Fox News the first time Secret Service agents saw the gunman he was already on the roof firing.

At that point, " a Secret Service Counter Sniper neutralized him," Guglielmi said.

4:50 p.m.

The Secret Service held a news conference in response to the assassination attempt of Trump at his rally Saturday, saying that the agency will not comment on the ongoing investigation. 

The agency also said there are no current changes to how officers will cover the Republican National Convention, which starts Monday. 

3:20 p.m.

The Pennsylvania State Police have released the names of the additional victims who were hurt at Saturday's rally. 

David Dutch, 57, of New Kensington, Pennsylvania, and James Copenhaver, 74, of Moon Township are currently recovering in a hospital. 

"These victims and their families are certainly in our thoughts today," Colonel Christopher Paris, Pennsylvania State Police Commissioner said in a news release. "The Pennsylvania State Police continue to work tirelessly alongside our federal, state and local partners as this investigation continues."

Governor Shapiro has ordered United States and Commonwealth flags to be flown at half-staff immediately in honor of Corey Comperatore, the spectator who was killed while protecting his family.

2:46 p.m.

Not long before shots rang out, rally goers noticed a man climbing to the top of a roof of a nearby building and warned local law enforcement, according to two law enforcement officials.

One officer climbed to the roof and encountered Crooks, who pointed his rifle at the officer. The officer retreated down the ladder and Crooks quickly took a shot toward former President Donald Trump, and that’s when the U.S. Secret Service counter snipers shot him, said the officials who spoke to The Associated Press on condition of anonymity to discuss an ongoing investigation.

2:24 p.m.

Donald Trump says he will be traveling to Milwaukee as planned for the GOP convention on Sunday afternoon.

"Based on yesterday’s terrible events, I was going to delay my trip to Wisconsin, and The Republican National Convention, by two days, but have just decided that I cannot allow a "shooter," or potential assassin, to force change to scheduling, or anything else," he wrote on his Truth social app. 

2:10 p.m.

President Joe Biden delivered brief remarks in which he called for unity and said he ordered an independent review of the security detail at Saturday's rally in Pennsylvania. 

He also said he'd be speaking again Sunday night "at greater length" about the situation. His remarks are expected at 8 p.m. ET from the Oval Office.

READ MORE: Biden says an assassination attempt is ‘not American’; will speak again Sunday night

12:30 p.m.

Pennsylvania Gov. Josh Shapiro says the man who was killed at a rally for former President Donald Trump was a former fire department chief from the area. 

He was identified as Corey Comperatore. Shapiro said Sunday that Comperatore "died a hero" and dove onto his family to protect them.

READ MORE: Trump rally shooting: What we know about the victims

11 a.m. 

Bomb-making materials were found inside of Crook's alleged vehicle. There were also bomb-making materials found at his home, authorities familiar with the situation told The Associated Press. 

The car was parked near the Trump rally on Saturday, according to a report by the Wall Street Journal. 

RELATED: Where is Donald Trump today?

10:22 a.m. 

Former first lady Melania Trump released a statement Sunday. 

She said someone "attempted to ring out Donald's passion - his laughter, ingenuity, love of music, and inspiration." 

"The core facets of my husband's life - his human side - were buried below the political machine. Donald, the generous and caring man who I have been with through the best of times and the worst of times," her statement continued. 

9:15 a.m.

In a new post on his social media network, Trump thanked "everyone for your thoughts and prayers yesterday, as it was God alone who prevented the unthinkable from happening."

"We will FEAR NOT, but instead remain resilient in our Faith and Defiant in the face of Wickedness," he wrote.

Trump also said, "Our love goes out to the other victims and their families" and he said he’s praying "for the recovery of those who were wounded, and hold in our hearts the memory of the citizen who was so horribly killed."

"In this moment, it is more important than ever that we stand United, and show our True Character as Americans, remaining Strong and Determined, and not allowing Evil to Win," he added.

8:23 a.m.

Trump campaign senior advisers said the former president is in "great spirits" and "doing well" in a staff memo obtained by The Associated Press. 

Donald Trump Jr. also told FOX News Digital in a statement that his father was in "great spirits."

7:36 a.m. 

Trump said he’ll still be speaking at the Republican National Convention, which kicks off Monday in Milwaukee, Wisconsin.  

Here's what to know about the convention. 

1:40 a.m.

The Federal Bureau of Investigation has identified 20-year-old Thomas Mathew Crooks as the shooter in the possible assassination attempt of Trump at his campaign rally in Pennsylvania.

"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 to Fox News Digital.

"This remains an active and ongoing investigation, and anyone with information that may assist with the investigation is encouraged to submit photos or videos online at FBI.gov/butler or call 1-800-CALL-FBI," the statement continued.

READ MORE: What we know about Thomas Mathew Crooks, the alleged shooter at Trump's rally

12:54 a.m. Sunday

Trump was seen exiting his plane early Sunday morning, the first time after his possible assassination attempt.

He suffered injuries to his ear after the shooting at his rally in Butler, Pennsylvania.

11:54 p.m.

Various law enforcement agencies hold a news conference in Butler, Pennsylvania, in regard to the assassination attempt of Trump. Officials have not publicly identified the shooter or determined a motive. 

However, FOX News reports the shooter has been identified as a 20-year-old male from the Local Butler County area, according to multiple reports, citing the FBI.

Other details about the suspect, including his name, have not been released.

The agency, which said it's taking the lead on the investigation, is asking anyone with information to call the tip line at 1-800-CALL-FBI.

10:55 p.m.

James Comer, a Kentucky Republican who is the House Oversight Committee chairman, invited U.S. Secret Service Director Kimberly Cheatle to testify at a hearing on Monday, July 22.

"Americans demand answers about the assassination attempt of President Trump," the committee posted on X, formerly known as Twitter, along with their official letter to Cheatle. 

10:30 p.m.

The White House said Biden spoke with Trump, who was injured during a shooting at his rally in Pennsylvania Saturday evening. 

9:40 p.m.

RELATED: FBI seeks information on Trump rally shooting

Law enforcement recovered an AR-style rifle at the scene of Trump's rally shooting, an Associated Press source said. 

8:49 p.m. 

The U.S. Secret Service released a statement saying that a suspected shooter fired multiple rounds during Trump's rally toward the stage from an elevated platform. The agency said the suspected shooter is deceased, one spectator was killed and two other spectators were hurt. FOX News reported earlier that two others were dead but the Secret Service said two others were injured. 

8:47 p.m.

Trump released a statement on social media:

"I want to thank The United States Secret Service, and all of Law Enforcement, for their rapid response on the shooting that just took place in Butler, Pennsylvania. Most importantly, I want to extend my condolences to the family of the person at the Rally who was killed, and also to the family of another person that was badly injured. It is incredible that such an act can take place in our Country. 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. Much bleeding took place, so I realized then what was happening. GOD BLESS AMERICA!"

8:19 p.m.

FOX News reported that the shooter in the Trump security incident in Pennsylvania was killed by a Secret Service counter sniper team.

8:15 p.m.

Biden addressed the nation, saying there's no place for violence. He plans to speak with Trump. 

Biden said "everybody must condemn" the attack. "There’s no place in America for this type of violence," he said. "It’s sick. It’s sick."

8:11 p.m.

FOX News reported an eyewitness told the BBC on Saturday that he saw a "man on top of a roof" near Trump's Pennsylvania rally.

RELATED: Trump injured, possibly shot at Pennsylvania rally; Fulton County co-defendants react

"We noticed the guy crawling up the roof of the building beside us, 50 feet away from us," the witness, whose name is Greg, said. "He had a rifle, we could clearly see him with a rifle."

Greg alerted police to the man on the roof, according to the BBC.

"Next thing you know, I’m thinking to myself why is Trump still speaking? Why have they not pulled him off the stage?" he said. "I’m standing there pointing at him... the next thing you know, five shots ring out."

7:56 p.m.

Biden issued a statement in regard to the shooting at Trump's rally:

I have been briefed on the shooting at Donald Trump’s rally in Pennsylvania.I’m grateful to hear that he’s safe and doing well. I’m praying for him and his family and for all those who were at the rally, as we await further information. Jill and I are grateful to the Secret Service for getting him to safety. There’s no place for this kind of violence in America. We must unite as one nation to condemn it.

7:51 p.m.

A law enforcement source told Fox News' Jacqui Henrich the shooter is dead, and two others have also died.

RELATED: Trump rally shooting: Texas leaders react to Pennsylvania rally chaos

7:40 p.m. 

According to FOX News, President Joe Biden has been briefed on the incident at former President Trump's rally, according to the White House.

RELATED: Shooting at Trump rally prompts reaction from allies, rivals: ‘Horrified’

The president was briefed by Kimberly Cheatle, Director of the United States Secret Service, Secretary Alejandro Mayorkas, Department of Homeland Security and Liz Sherwood-Randall, Assistant to the President and Homeland Security Advisor

White House staff who participated include Jeff Zients, Assistant to the President and Chief of Staff, Steve Ricchetti, Assistant to the President and Counselor to the President and Annie Tomasini, Assistant to the President and Deputy Chief of Staff, a White House official said.

7:29 p.m.

Butler County district attorney Richard Goldinger said in a phone interview that the suspected gunman was dead and at least one rally attendee was killed.

7:24 p.m.

The U.S. Secret Service tweeted that officers have launched an "active investigation" and that Trump is safe.

6:15 p.m.

Possible shots were heard while former President Donald Trump was speaking before he was whisked off-stage. As he was escorted off the stage by Secret Service agents, Trump held his fist in the air as chants of "USA! USA!" echoed through the crowd.

Live microphones picked up the Secret Service agents' comments as they moved the former president to safety: "Shooter is down!" "Are you ready! On you! Move! We're clear!"

His motorcade had left the venue. His condition was not immediately known.

Police began vacating the fairgrounds shortly after Trump left the stage.

The Associated Press contributed to this report. This is a developing story. Check back for updates.