US media reports say the 20-year-old Thomas Mathew Crooks who tried to assassinate former President Donald Trump first came to law enforcement’s attention at Saturday’s rally when spectators noticed him acting strangely outside the campaign event. The tip sparked a frantic search but officers were unable to find him before he managed to get on a roof, where he opened fire, according to The Associated Press (AP).

In the wake of the shooting that killed one spectator, investigators were reportedly hunting for any clues about what may have drove Thomas Matthew Crooks, of Bethel Park, Pennsylvania, to carry out the shocking attack.  The FBI said they were investigating it as a potential act of domestic terrorism, but the absence of a clear ideological motive by the man shot dead by Secret Service led conspiracy theories to flourish.

The FBI said it believes Crooks, who had bomb-making materials in the car he drove to the rally, acted alone.  Investigators have found no threatening comments on social media accounts or ideological positions that could help explain what led him to target Trump.  

Trump said on social media the upper part of his right ear was pierced in the shooting.

Two spectators were critically injured, while a former fire chief from the area, Corey Comperatore was killed.  

Relatives of Crooks didn’t respond to numerous messages from AP.  His father, Matthew Crooks, told CNN late Saturday that he was trying to figure out “what the hell is going on” but wouldn’t speak about his son until after he talked to law enforcement.  An FBI official told reporters that Crooks’ family is cooperating with investigators.

Thomas Matthew Crooks; photo / the BBC

Crooks’ political leanings were not immediately clear.  Records show Crooks was registered as a Republican voter in Pennsylvania, but federal campaign finance reports also show he gave US$15.00 to a progressive political action committee on Jan. 20, 2021, the day Biden was sworn into office.

According to AP, Crooks graduated from Bethel Park High School in 2022.  His senior year, Crooks was among several students given an award for math and science

Crooks reportedly tried out for the school’s rifle team but was turned away because he was a bad shooter, said Frederick Mach, a current captain of the team who was a few years behind Crooks at the school.

CNN says US president emphasizes the need “to lower the temperature “ in politics after attempted assassination of Donald Trump. 

The BBC reports that Thomas Crooks was from Bethel Park in Pennsylvania, about 70km (43 miles) from the site of the attempted assassination, and graduated in 2022 from Bethel Park High School with a $500 prize for math and science, according to a local newspaper.

Crooks reportedly worked in a local nursing home kitchen just a short drive away from his home.