Over 30 hours after a bullet pierced Donald Trump’s ear at a rally ahead of the US’ biggest election, the motive behind the high-profile assassination attempt remains unknown. The Federal Bureau of Investigation (FBI) has begun probing the incident as a “potential domestic terrorism act”.

Thomas Crooks, the 20-year-old gunman who opened fire at Trump, was shot dead on the spot by Secret Service snipers. He appears to have acted alone but there’s more to the probe, said the FBI.

Senior FBI official Robert Wells said the counterterrorism division and criminal divisions are working together to determine the motive.

Officials also said Crooks did not carry any identity document to the rally and are trying to run a DNA test to get biometric confirmation.

Even the suspect’s father, Matthew Crooks, 53, is trying to figure out what happened. He told CNN he would wait until he spoke to law enforcement before speaking about his son.

Saturday’s attack left Trump with a bloodied face, sparking a wave of sympathy for the Republican who is set to be Presidential nominee for the third time. Trump, who believes the attack has changed election discourse, is now trying to galvanize his supporters by exhibiting defiant resilience.

Conspiracy theories claim the attack was “staged”, pointing to the “iconic” pic showing Trump with a bloodied face holding his fist in air – most of the claims came from the left-leaning users, usually seen as anti-Trump.

Who is Thomas Crooks?

Thomas Crooks was a 20-year-old resident of Pennsylvania. He graduated from Bethel Park High School, Penn in 2022. State voter records showed he was a registered Republican – a member of Trump’s party.

Meanwhile, a 2021 Federal Election Commission filing suggests Crooks had made a $15 donation when he was 17 to a political action committee that raises money for left-leaning and Democratic politicians.

He had received a $500 “star award” from the National Math and Science Initiative, according to Pittsburgh Tribune-Review.