The motives, opinions, affiliations and potential allies of the 20-year-old gunman responsible for the assassination attempt on Donald Trump remain unknown, authorities say.
The FBI identified Thomas Matthew Crooks as the shooter behind the attack at the Pennsylvania rally, which injured the former president and left a 50-year-old volunteer firefighter dead.
Two others were also critically injured in the incident but remain in a stable condition.
Crooks carried out the attack from a rooftop of a nearby building and was killed by Secret Service snipers shortly after he opened fire.
Investigators have since found materials for explosive devices in his car and potentially at his residence in Bethel Park, Pennsylvania.
They have not, according to authorities, found any kind of manifesto or motivation for the attack.
Crooks was not under FBI surveillance or investigation prior to the attack.
US President Joe Biden said during a live address on Sunday local time: “We do not know the motive of the shooter yet.
“We don’t know his opinions or affiliations. We don’t know if he had help or support, or if he communicated with anyone.
“Law enforcement officials, as I speak, are investigating those questions.”
A community ‘shocked and saddened’
Crooks was a resident of Bethel Park, Pennsylvania, about an hour away from where the rally was held.
Because he was not carrying identification, the FBI was forced to analyse his DNA to confirm his identity.
Crooks’s father, Matthew Crooks, told CNN late on Saturday night he was trying to find out “what the hell is going on” but would “wait until I talk to law enforcement” to give comment.
Crooks was a registered Republican, and the upcoming election would have been the first time he was old enough to vote in a presidential race.
His father was a Libertarian and his mother was a Democrat, something a city council representative told the New York Times was typical for the area.
“You’ve got a large spattering of different backgrounds and ideals, and definitely have a lot of mixed households in Bethel Park,” Dan Grzybek told the newspaper.
Crooks graduated from Bethel Park High School in 2022, according to a statement from the school district.
“Our school district will cooperate fully with the active law enforcement investigation surrounding this case, and as such, we are limited in what we can publicly disclose,” the statement read.
When Crooks was 17 he made a USD 15 donation to ActBlue, a political action committee that raises money for left-leaning and Democratic politicians, according to a 2021 Federal Election Commission filing.
The donation was earmarked for the Progressive Turnout Project, a national group that rallies Democrats to vote.
The groups did not immediately respond to a Reuters request for comment.
He had been working as a dietary aide at Bethel Park Skilled Nursing and Rehabilitation Centre since graduating from the Community College of Alleghany County in May.
The center’s administrator, Marcie Grimm, said in a statement she was “shocked and saddened” to learn of his involvement.
“Thomas Matthew Crooks performed his job without concern and his background check was clean,” she said.
“We are fully cooperating with law enforcement officials at this time … We condemn all acts of violence.”
An ongoing investigation searching for answers
FBI officers have said they believe Crooks acted alone, and that his social media activity contained no threatening language.
They have not found any history of mental health issues.
Dozens of law enforcement vehicles were stationed outside a residence listed at the address on Crooks’s voter registration record.
Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives were on the scene and a bomb squad was at the residence.
The perimeter was guarded on Sunday by yellow police caution tape.
An Allegheny County Police vehicle was parked outside.
“It’s insanity that anyone would do this,” 30-year-old resident Dan Maloney told reporters.
Various classmates have told media he was intelligent, polite, and quiet.
Two officials spoke to The Associated Press on the condition of anonymity, saying an AR-style rifle was recovered at the scene.
The FBI later confirmed Crooks used an AR-style 556 rifle, which they believe was legally purchased by the suspect’s father.
AR-style rifles are common in mass shootings in the US, said David Smith from the University of Sydney’s United States Studies Centre.
They are affordable, lightweight and semi-automatic, meaning they can fire multiple rounds quickly.
Crooks was a member of the Clairton Sportsmen’s Club in Pennsylvania, according to the club’s lawyer.
“Obviously, the club fully admonishes the senseless act of violence that occurred yesterday,” Robert Bootay said in a statement to CNN.
He did not provide any further information about the last time that Crooks visited the club or whether he used the rifle range.
Bruce Piendl, owner of Allegheny Arms and Gunworks in Bethel Park, said guns were part of the culture in the area.
“You have to understand in western Pennsylvania we have a rich tradition of hunting and fishing and outdoor stuff,” he said.
“Within 10 miles (16km) of here, there are a ton of gun clubs.”
Mr Piendl said his records show he did not sell any firearms to the shooter but declined to say whether he sold any to his family.
“That’s between me and God,” he said.
Federal law enforcement officials told the New York Times Crooks did not have an unusual online history, playing chess, video games and learning how to code.
However, Discord said he had an account on the instant messaging platform.
“We have identified an account that appears to be linked to the suspect; it was rarely utilised and we have found no evidence that it was used to plan this incident or discuss his political views,” Discord said in a statement.
Meta, the parent company of Facebook and Instagram, did not immediately respond to questions on whether the platforms had removed any accounts related to the suspect.
By Brianna Morris-Grant, Annika Burgess and wires. Australian Broadcasting Corporation
