The gunman who tried to assassinate former President Donald Trump had researched the attempted killing of the Slovakian prime minister in May, Federal Bureau of Investigation (FBI) officials said on a call to reporters on Monday, The Washington Post reported.

Thomas Matthew Crooks, the shooter at Trump’s July rally in Butler, Pennsylvania, had researched mass shootings and the attempted assassination of Slovakian Prime Minister Robert Fico, according to a call with the FBI Monday, The Washington Post reported. The details, which FBI officials said demonstrated the shooter’s “careful planning” of the attack, were revealed as agents continue to pore through data from his cellphones, laptop, and other devices. (RELATED: Trump Announces Return To Butler For New Rally After Assassination Attempt)

As of the call Monday, agents have conducted more than 450 interviews, with no sources, including Crooks’s own parents, seeming to have any knowledge of the attack before it occurred, according to the Washington Post.

“We believe the suspect made significant efforts to conceal his activities,” Kevin Rojek, the special agent in charge of the FBI’s Pittsburgh Field Office, told The Washington Post.

As a result, Crooks’s motive for the shooting remains unclear, according to The Washington Post.

🚨TRUMP to give “victim interview” to FBI as they increase their probing of the assassination attempt in Butler, PA

Per FBI during agency briefing pic.twitter.com/dPCGk7uEUa

— Diligent Denizen (@DiligentDenizen) July 29, 2024

FBI officials also revealed to Yhe Washington Post Monday that Trump has agreed to be interviewed as part of their investigation.

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

Trump was shot in the ear on July 13, having turned his head in the nick of time to look at a chart detailing rates of illegal immigration. The gunman was noticed by law enforcement approximately 50 minutes before Trump took the stage to address the crowd, but officials failed to act, United States Secret Service and FBI officials revealed in a July 17 briefing.

Crooks also reportedly flew a drone over the Pennsylvania site hours before the event.

U.S. Secret Service Director Kimberly Cheatle resigned from her position on Tuesday over the incident, after providing evasive testimony before the House Oversight Committee the day prior.

Slovakian Prime Minister Robert Fico was shot several times by an assailant in May after successfully winning a third term, campaigning on a pro-Russian message.

All content created by the Daily Caller News Foundation, an independent and nonpartisan newswire service, is available without charge to any legitimate news publisher that can provide a large audience. All republished articles must include our logo, our reporter’s byline and their DCNF affiliation. For any questions about our guidelines or partnering with us, please contact licensing@dailycallernewsfoundation.org.