The gunman who tried to kill former president Donald Trump conducted internet searches related to power plants, mass shooting events and the attempted assassination this year of Slovakia’s prime minister, FBI officials said Monday, offering new details about what they described as the gunman’s “careful planning” for the attack.

The details, including about Thomas Matthew Crooks’s interest in the attempted killing of Prime Minister Robert Fico, were released as agents continue to unpack data pulled from the gunman’s cellphones, laptop and other digital devices. Fico was shot and gravely wounded in Slovakia in May.

In a call with reporters on Monday, FBI officials said Trump has agreed to an FBI interview about the assassination attempt against him at a July 13 campaign rally in Butler, Pa.

“We want to get his perspective as to what he observed,” said Kevin Rojek, who heads the FBI’s Pittsburgh field office, which is leading the investigation. “It is a standard interview we would do for any other victim of crime.”

Crooks’s motive for the shooting is still unclear, FBI officials said, and they have not yet found evidence tying any other people to the attack. The officials said they plan to continue searching through the gunman’s phones and his gaming and social media accounts to identify a possible motive or any indication that he may have worked with an accomplice.

He used aliases and at least some encrypted communication accounts to purchase firearm supplies and materials to construct explosive devices, the officials said.

Trump was speaking at an outdoor rally when Crooks, 20, opened fire from a rooftop just outside the security perimeter. The gunman fired at least eight shots, killing one person in the crowd, critically injuring two others and wounding Trump before being killed by a Secret Service sniper.

The FBI said last week that a bullet or bullet fragment grazed the former president’s ear.

Investigators discovered two explosive devices in Crooks’s car parked at the rally site. The devices were capable of explosions, but both receivers were in the “off position” when they were found, the officials said Monday.

Agents have conducted more than 450 interviews, including with Crooks’s parents, who did not seem to have any indication of the attack before it occurred and have been cooperating with authorities, officials said.

“We believe the suspect made significant efforts to conceal his activities,” Rojek said.

While the FBI has focused primarily on the shooter and his actions before the attempted assassination, multiple additional investigations are focused on the security failures that allowed a man with a rifle to obtain a perch from which to shoot at the president from about 150 yards away.

Rojek said the gunman used heating and cooling equipment near one building to climb onto the roof, then traversed across multiple other roofs before settling on the spot from which he would launch the attack.

Investigators have attempted to reconstruct the gunman’s activities leading up to the early evening attack. They said he drove to the rally around 11 a.m. and spent about an hour there before driving back home, about 50 miles away.

Later that day, he told his parents he was going to a shooting range, but actually drove back to the rally site. He arrived at around 3:45 p.m. and flew his drone around the site for about 10 minutes, officials said. Because there was no memory card in the drone, investigators could not determine what information about the site’s security the gunman gleaned from it, officials said.

He left the rally site for about an hour before returning to get in position for his eventual attack, officials said. He carried with him a backpack and AR-15 style weapon with a collapsible stock, which is an enhancement to weapons that makes them more compact.

Officials said they are still determining how he was able to conceal the weapon at the rally.

The guman was a “highly intelligent” man who attended college and maintained steady employment, officials said. They indicated that they have struggled to identify much about him or his potential motive, in part because he didn’t have many friends.

His social circle mostly consisted of his immediate family, officials said. The family owned more than a dozen firearms and the younger Crooks became interested in firearms as a hobby years ago. That hobby transformed into more formal shooting training and lessons in September 2023, according to officials.

His father, who originally purchased the gun used in the attack in 2013, legally transferred ownership of the weapon to his son last year.

“We believe he had few friends and acquittances throughout his life,” Rojek said.

This is a developing story and will be updated.