BETHEL PARK, Pa. – FBI Director Christopher Wray said that his agency is still not certain how Thomas Matthew Crooks accessed the roof of the building where he took aim at former President Donald Trump – but they don't believe he used a ladder.

Despite the fact that a "bloodied receipt" found on Crooks' dead body included a 5-foot ladder purchase, Wray told the House Judiciary Committee on Wednesday, his agency believes that "the subject climbed onto the roof using some mechanical equipment, on the ground and vertical piping on the side of the AGR building" on July 13.

"In other words, we do not believe he used a ladder to get up there," he said in Washington, D.C. 

TIMELINE: TRUMP ASSASSINATION ATTEMPT

Thomas-matthew-crooks

Thomas Matthew Crooks is pictured in front of the Butler Fairgrounds in the aftermath of the attempted assassination of the former president on July 14, 2024 in Butler, Pennsylvania.  (Bethel Park School District/Getty Images)

"We did not find the ladder at the scene," Wray told Rep. Steve Cohen. "He did buy a ladder. But the ladder was not found at the scene."

"The ladder didn't have any feet on it – it didn't walk off," Cohen joked in response.

FBI DIRECTOR CHRISTOPHER WRAY TESTIFIES ABOUT TRUMP RALLY ASSASSINATION ATTEMPT

Buildings that are adjacent to The Butler Farm Show, site of a campaign rally for Republican presidential candidate former President Donald Trump,

Buildings that are adjacent to The Butler Farm Show, site of a campaign rally for Republican presidential candidate former President Donald Trump, are seen Monday, July 15, 2024, in Butler, Pa. Thomas Crooks fired from the roof of the building complex and wounded Trump on July 13 during an assassination attempt.  (AP Photo/Gene J. Puskar)

Butler Farms Crooks building

Pictured is the building that Thomas Crooks clambered up to shoot at former President Donald Trump – former NYPD inspector Paul Mauro suspects that Crooks used the hallway adjoining the two buildings to get onto the roof and stashed his AR-15 in the air conditioning unit pictured. (Fox News)

The Home Depot where Crooks purchased the ladder is a brief drive from his family's home on Milford Drive in Bethel Park. Home Depot has not responded to Fox News Digital's requests for comment.

Wray said outdoor events, like concerts and political rallies, are "often... particularly challenging to secure adequately, because the range of threats that can face them are higher."

TRUMP SHOOTER MADE CHILLING GOOGLE SEARCH ON DAY HE REGISTERED FOR BUTLER RALLY

Wray speaks to Senate subcommittee

FBI Director Christopher Wray testifies during a Senate Appropriations Subcommittee hearing on the FBI's proposed budget for the 2025 fiscal year on June 4, 2024 in Washington, D.C.  (Samuel Corum/Getty Images)

"In addition to that... just threats to public officials, including politicians, is an increasingly pervasive part of today's landscape. And so that adds to the challenge," Wray continued.

Using drone footage from the scene of the shooting at the Butler Farm Show grounds, Fox News contributor Paul Mauro pointed out possible access points to Crooks' vantage point earlier this week. 

A hallway adjoining the building to another beside it provided an access point where Crooks could have clambered onto the roof, Mauro said. An air conditioning unit seen from above may be where he stashed his AR-15 ahead of the rally, sources told Mauro. 

TRUMP SHOOTER MADE HOME DEPOT VISIT PRIOR TO ASSASSINATION ATTEMPT

Exterior view of The Home Depot where Donald Trump's would-be assassin purchased a ladder.

Exterior view of a Home Depot store at 4000 Oxford Drive, Bethel Park, Pennsylvania, Tuesday, July 16, 2024. The store is reportedly the location where Thomas Crooks bought a ladder before he attempted to assassinate former President Donald Trump in Butler, Pennsylvania on Saturday. (Sarah Rumpf / Fox News Digital)

Wray's testimony on Wednesday revealed other new details: on the day he registered to attend the rally, Crooks conducted a Google search for "how far away was Oswald from Kennedy."

Wray also elaborated on Crooks' stash of weapons, including two explosive devices found in his vehicle near the Butler rally and one more in his home.

Building used by Trump rally shooter

Two FBI investigators scan the roof of AGR International Inc, the building adjacent to the Butler Fairgrounds, from which shooter Matthew Thomas Crooks fired at former President Trump on July 13. (Jeff Swensen/Getty Images)

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Based on his online activity, Wray said, 20-year-old Crooks "became very focused on former President Trump and his rally" around July 6.

"That's a search that obviously is significant in terms of his state of mind," Wray added.