FBI officials disclosed on Monday that Thomas Matthew Crooks, the 20-year-old who attempted to assassinate Donald Trump at a rally earlier in July, had been accumulating bomb-making materials and purchasing gun-related items for over a year before the Butler rally shooting.

According to the Wall Street Journal, Crooks made 25 different online purchases of gun-related items between spring 2023 and mid-2024, along with six purchases of materials used in explosives.

Kevin Rojek, the FBI special agent in charge in Pittsburgh, stated that Crooks had searched online for information related to mass shooting events, power plants, improvised explosive devices, and the assassination attempt on Slovakia’s prime minister.

“While the FBI’s investigation may not have yet determined a motive, we believe the subject made significant efforts to conceal his activities. Additionally, we believe his actions can also show careful planning ahead of the campaign rally,” Rojek said.

The online purchases were made under an alias, and Crooks stored gun equipment and chemicals in the Bethel Park, Pennsylvania home he shared with his parents. Rojek noted that Crooks’ parents were not alarmed because he had long been interested in science and experiments.

“For that reason, they weren’t concerned that it was focused on committing an attack of this nature or harming other people. The parents have said in their interviews that they had no advanced knowledge of any of this,” Rojek said, adding that the gunman’s parents have been credible and cooperative.

The FBI has interviewed over 450 people in its investigation into how Crooks managed to open fire from a rooftop on a nearby building, injuring Trump and two other rally attendees and killing another. Among those interviewed were dozens of Crooks’ former classmates, co-workers, and family members.

Trump has also agreed to sit for an interview with the FBI as part of their investigation.

“We want to get his perspective on what he observed, just like any other witness to the crime,” Rojek said. “It is a standard victim interview like we would do for any other victim of crime.”

The FBI’s profile of Crooks depicts him as a highly intelligent loner who attended college and held a steady job at a nursing home. His primary social circle was limited to immediate family members. While the motive remains unclear, the FBI has requested information from 86 companies regarding Crooks’ online accounts, indicating he had minimal interaction with others, even virtually.