The 20-year-old Pennsylvania man who tried to assassinate Donald Trump had photos on his phone of the former Republican president, President Joe Biden and other officials, including Attorney General Merrick Garland and FBI Director Chris Wray, according to two people familiar with the matter.

Investigators searching Thomas Matthew Crooks’ devices have also found that the shooter looked up the dates for the Democratic National Convention as well as Trump’s appearances, according to the people who spoke to The Associated Press on the condition on anonymity to discuss details of the ongoing probe.

The FBI has been searching for clues into what drove Crooks to open fire at Saturday’s campaign rally in Butler, Pennsylvania, in an attempt to assassinate the GOP presidential nominee. The FBI has said they are investigating the shooting as a potential act of domestic terrorism but have yet to find a clear ideological motive. The FBI gained access to Crooks’ cellphone, scoured his computer, home and car, and interviewed more than 100 people so far.

Crooks killed one rallygoer and seriously wounded two others. Trump suffered an ear injury but was not seriously hurt, appearing just days later at the Republican National Convention in Milwaukee with a bandage over the wound.

The shooter had also searched for information about major depressive disorder, according to three people familiar the investigation. But investigators have not yet determined whether he was actually diagnosed with the disorder, one of the people said. Studies have shown that the vast majority of people with mental illnesses are not violent, and experts say most people who are violent do not have mental illnesses.

On a conference call with reporters Sunday, Kevin Rojek, the special agent in charge of the Pittsburgh field office, said: “We have no indication of any mental health issues.”

Crooks used an AR-style rifle, which authorities said was purchased legally by his father. Investigators also found he brought multiple loaded magazines. He also bought 50 rounds on the day of the shooting. Authorities found a bulletproof vest in his car and another rudimentary explosive device at his home. Over the past few months he had received several packages there, including some that had potentially hazardous material.

The shooting raised serious questions about why law enforcement was unable to stop the man from getting on a roof and opening fire. Multiple investigations into the security failures are underway, including a Department of Homeland Security inspector general’s probe into the Secret Service’s handling of security.

The Republican chairman of the House Oversight and Accountability Committee issued a subpoena Wednesday to Secret Service Director Kimberly Cheatle for her to appear before the committee on Monday. Republican have been calling for Cheatle to resign in the wake of the shooting, though she has said she has no intention do so.

Local law enforcement had noticed Crooks pacing around the edges of rally, shouldering a big backpack and peering into the lens of a rangefinder toward the rooftops behind the stage where the president later stood, officials have told the AP.

An image of Crooks was circulated by officers stationed outside the security perimeter. Witnesses later saw him climbing up the side of a squat manufacturing building that was within 135 meters (157 yards) from the stage. He then set up his AR-style rifle and lay on the rooftop, a detonator in his pocket to set off crude explosive devices that were stashed in his car parked nearby.

Butler Township Manager Tom Knights said in a statement to The Associated Press on Thursday that officers were searching for a suspicious person around the time Trump arrived. Officers didn’t find him around the building, so a Butler Township officer attempted to gain access to the roof by being hoisted up by another officer, Knights said. The officer spotted a person on the roof, and that person pointed a rifle at the officer, Knights said.

“The officer was in a defenseless position, and there was no way he could engage the actor while holding onto the roof edge,” Knights said. The officer fell to the ground and Butler Township officers “immediately communicated the individuals location and that he was in possession of a weapon,” Knights said.

Moments later, Crooks started firing, sending panicked spectators ducking for cover as Secret Service agents shielded Trump and pulled him from the stage. Two counter-sniper teams were stationed on buildings behind Trump, and the team further away from Crooks fired once, killing him.

(AP)