The gunman in the attempted assassination of former President Donald Trump is believed to have done a Google search one week before the shooting of “How far away was Oswald from Kennedy?” FBI Director Christopher Wray said Wednesday, revealing new details about a suspect he said had taken a keen interest in public figures but had otherwise not left behind clear clues of an ideological motive.

The search, recovered from a laptop tied to 20-year-old Thomas Matthew Crooks, is a reference to Lee Harvey Oswald, the shooter who killed President John F. Kennedy from a sniper’s perch in Dallas on Nov. 22, 1963.

The revelation to the House Judiciary Committee was part of a collection of new details offered by Wray about the July 13 shooting at a Trump rally in Butler, Pennsylvania. The FBI’s investigation has thrust the bureau into a political maelstrom months before the presidential election, with lawmakers and the public pressing for details about what may have motivated Crooks in the most serious attempt to assassinate a president or presidential candidate since President Ronald Reagan was shot in 1981.

The FBI has built out a detailed timeline of Crooks’ movements and online activity, but the precise motive — or why Trump was singled out — remains elusive, Wray said.

“A lot of the usual repositories of information have not yielded, anything notable in terms of motive or ideology,” Wray said. He did note that Crooks had grown interested in public officials — besides Trump, Crooks also had photos on his phone of Democratic President Joe Biden and other prominent figures — and in the days before the shooting had appeared particularly consumed by Trump, the Republicans’ White House nominee.

Wray also said that Crooks, about two hours before the shooting, had flown a drone about 200 yards (180 meters) from the rally stage where Trump would later stand and that Crooks used the device to livestream and watch footage. The use of the drone so close the rally site just hours before Trump took the stage for the rally add to the questions about the security lapses preceding the event.

Wray pledged to lawmakers that the FBI would “leave no stone unturned” in its investigation.

“I have been saying for some time now that we are living in an elevated threat environment, and tragically the Butler County assassination attempt is another example — a particularly heinous and public one — of what I’ve been talking about,” Wray said.

The hearing had been scheduled well before the shooting, as part of the committee’s routine oversight of the FBI and the Justice Department. Questions about the shooting dominated the session.

Despite being appointed by Trump, Wray typically faces antagonistic questions from the Republican-led panel, a reflection of lingering discontent over the FBI’s investigation into potential ties between Russia and the 2016 campaign, when Trump defeated Democrat Hillary Clinton.

That sentiment was made clear early in the hearing when the committee chairman, Rep. Jim Jordan, R-Ohio, told Wray: “I’m sure you understand that a significant portion of the country has a healthy skepticism regarding the FBI’s ability to conduct a fair, honest, open and transparent investigation.”

The FBI so far has avoided the same level of scrutiny over the shooting directed at the Secret Service over security failures that preceded the shooting and has led to the the resignation of Director Kimberly Cheatle,

The FBI has said it is investigating the shooting, which killed one rallygoer and seriously injured two others, as an act of domestic terrorism and an attempted assassination. Trump’s campaign said the presumptive GOP nominee was doing “fine” after the shooting, which Trump said pierced the upper part of his right ear.