Trump’s potential assassin Thomas Matthew Crooks researched former mass murderer Ethan Crumbley and his family before the attack

The suspect in the Trump rally shooting searched online for information about the arrest of a Michigan mass shooter and his parents, who were charged in a 2021 high school shooting. He visited websites looking for instructions on how to build explosives. And in the minutes before he fired shots in an assassination attempt on Donald Trump, he took a screenshot of an image from a livestream of the rally in Butler, Pennsylvania.

A week before the shooting, Thomas Matthew Crooks searched online for the date of the Democratic National Convention and the location where Trump planned to speak, as well as other searches for Trump and President Joe Biden.

Those details were released by FBI and U.S. Secret Service officials in a briefing Wednesday with lawmakers and others familiar with the investigation. The previously unreleased information documents the scope of the investigation, including a detailed chronology of the bomber’s actions leading up to his attack and the failure of law enforcement to prevent it.

SEE ALSO: James Crumbley told his son at a meeting before the shooting that there were “people he could talk to”

Investigators remain baffled as to the possible motives for Saturday’s assassination attempt on the former president. They find little evidence that the attack was motivated by political or ideological intentions.

But the attacker’s latest trail on the Internet has given investigators a detailed picture of his possible state of mind before the attack. FBI behavioral experts are building a profile of Crooks based on the findings, the FBI told lawmakers.

A new theory from investigators, based in part on the timing and topics of his online searches, suggests that the shooter was planning a mass murder and that the proximity and timing of the Trump affair provided the best opportunity to do so, according to a U.S. official familiar with the matter.

Unlike other mass murderers who often leave manifestos or documents explaining their attacks, Crooks left no clues in his bedroom or on the Internet.

Investigators found simple explosive devices, a bulletproof vest, more magazines of the type he used in the attack and a drone in his car, according to officials who briefed lawmakers on Wednesday. They also found 14 firearms and more explosives in the family home, as well as a second cellphone, a laptop and a hard drive.

Investigators focused on Crooks’ online activity in the months and days before the attack. Family members and people he worked with described him as quiet and solitary, but gave no indication that he showed signs of planning an attack. In April, he searched websites for information about major depressive disorder and treatment options for depressive crises.

On his main phone, investigators found an image of the arrest photo of Ethan Crumbley – the student who shot and killed four classmates at a Michigan high school in 2021 – as well as information about Crumbley and his parents, who were both found guilty of manslaughter. It was the first time the parents of a school shooter had been prosecuted.

RELATED: Ethan Crumbley, suspect in Oxford High School shooting, appeals life sentence

Three days after the Trump campaign announced the rally in Butler, a western Pennsylvania town about an hour from Crooks’ home, Crooks searched the internet countless times for well-known politicians and political events. He searched for the date and location of the Democratic National Convention, which will be held in Chicago in August, and the location of the Trump rally. He also searched for information about Trump, Biden and other major political figures.

On the day of the rally, Crooks searched the Internet several times, including for pictures of the location of Trump’s speech and for a gun store near his home where he had purchased ammunition that day.

Investigators found data showing Crooks had visited the rally site a week before the event. On the morning of the rally, he visited the farm where the rally was to be held for over an hour. He then went home and investigators believe he found an AR-15 rifle that belonged to his father. Crooks’ father told investigators he saw his son leave the house with the rifle and believed he was on his way to a shooting range the two frequently visited.

On the day of the rally, his parents tried to reach Crooks to find him. He did not respond.