A 20-year-old gunman opened fire at ex-President Donald Trump on Saturday in what is being dubbed the most serious attempt to assassinate a presidential candidate since 1981.
Thomas Matthew Crooks, from Bethel Park, Pennsylvania, was identified as the shooter by the FBI following the shocking incident that took place during a rally in Butler.
It has since emerged through federal campaign finance records that the gunman was a registered Republican who had previously made a $15 donation to the liberal ActBlue political action committee on January 20, 2021 - Biden's Inauguration Day.
Officials have released no additional information about the shooter.
'This remains an active and ongoing investigation,' the FBI said in a statement early Sunday.
Thomas Matthew Crooks, 20, was identified by the FBI as the shooter in the Saturday night Donald Trump assassination attempt. He was later gunned down and killed by the Secret Service
Donald Trump was addressing a cheering crowd at a rally in Butler, Pennsylvania, before he was shot in the ear
Secret Service swarmed to his side and ushered the former-President away while he was seen with blood pouring down his face
Trump emerged from the cover of the suited agents and raised a fist, shouting: 'Fight, fight, fight' before he was taken to hospital
During the attack, Crooks appeared to be wearing merchandise promoting one of YouTube's most popular channels devoted to firearms - Demolition Ranch - NBC News reported.
According to Pennsylvania's public court records, Crooks had no criminal history and officials claimed they are still working towards identifying a motive behind the shooting.
Crooks appeared to have graduated in 2022 from Bethel Park High School, and received a $500 'star award' that year from the National Math and Science Initiative, a report from The Tribune-Review in western Pennsylvania.
In an online recording of the 2022 graduation ceremony, he can be seen crossing the stage as the crowd applauds him, before briefly posing with a school official and accepting his diploma.
His father, Matthew Crooks told CNN late on Saturday night that he was trying to figure out 'what the hell is going on' but would 'wait until I talk to law enforcement' before speaking about his son.
On Saturday, Crooks opened fire from a rooftop 150 yards from where Trump was on stage addressing thousands of fans in Butler at 6:15pm.
Footage of the moment shows Trump suddenly grabbing his ear as blood poured down his face after at least eight shots were fired in his direction.
The crowd began screaming and fleeing the venue as Secret Service agents swarmed around the injured former-President.
But in a show of strength, Trump emerged from the cover of the suited agents and raised a fist, shouting: 'Fight, fight, fight', before he was ushered away from the chaotic scenes and sent to hospital.
Crooks had killed a member of the crowd and critically injured two others before he was gunned down by the Secret Service.
The shooter was killed after he fired from an 'elevated position' outside the outdoor rally venue, according to the Secret Service.
Images show at least four members of law enforcement surrounding the bloody gunman and the AR-15-type semiautomatic rifle he used on the roof, while they point their guns towards his body.
Following the shocking incident, Trump was then seen just hours later walking down the stairs of his plane, Trump Force One, in Newark, New Jersey.
His deputy communications director Margo Martin posted the video to X, formerly Twitter, with the message: 'Strong and resilient'.
Republican presidential candidate former President Donald Trump is helped off the stage by US Secret Service agents at a campaign event in Butler
The former US president was seen with blood on his right ear as he was surrounded by security agents, who hustled him off the stage as he pumped his first to the crowd
Snipers stand on a roof at Republican presidential candidate and former US President Donald Trump's campaign rally in Butler
The former-President appears to have Secret Service agents in front and behind him as he disembarks the plane.
'He will never stop fighting for America,' Margo Martin wrote.
Current President Joe Biden also took to X following the attack to condemn the assassination attempt, and it has since been confirmed that he has spoken with Trump following the shooting.
'I have been briefed on the shooting at Donald Trump's rally in Pennsylvania,' he wrote in a post.
'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'.
Several other world leaders followed suit.
UK Prime Minister Keir Starmer said he is 'appalled' by the 'shocking scenes' and political violence has 'no place in our societies'.
Barack Obama, who was president before Trump until 2016, said 'we should all be relieved' he wasn't seriously hurt.
And Former UK Prime Minister Boris Johnson added: 't is a miracle that Donald Trump escaped an attempted assassination'.
Donald Trump's daughter, Ivanka Trump, also shared a message acknowledging the 'love and prayers' for her father and for the other victims of the 'senseless violence'.
Taking to X, she wrote: 'I am grateful to the Secret Service and all the other law enforcement officers for their quick and decisive actions today.
'I continue to pray for our country. I love you Dad, today and always.'
Speaking out for the first time following the assassination attempt, Trump thanked law enforcement officers and the Secret Service for their 'rapid response'.
He added: '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'.
