The 20-year-old would-be assassin fired at former President Trump in Pennsylvania over the weekend. He had a Home Depot receipt for a ladder, sources told NBC News.
Investigators found the receipt on Thomas Matthew Crooks. He was fatally shot by Secret Service agents on Saturday.
Officials are investigating if Crooks used the ladder to access the roof. That's where he shot Trump in the ear, sources said.
More than a dozen firearms were found in the Crooks family home. The shooter's father called police about a missing AR rifle after the incident.
The rifle used was purchased legally and might have been his father's.
Law enforcement is checking if the bullets were bought at Allegheny Arms and Gun Works. The store is close to the Crooks' family home.
Videos show rally-goers alerting law enforcement to Crooks' presence on the roof before the shooting.
Officials said Crooks acted alone in the attempt on Trump but are still investigating.
Few details have emerged about Crooks' background or motivation. Locals said he was relentlessly bullied in high school and was a loner.
Classmates described him as conservative but not vocal about his views.
He was a registered Republican but donated $15 to the Progressive Turnout Project in 2021.
Crooks, a member of a shooting club, often wore hunting outfits to school and was mocked for them.
Former Buffalo Township Volunteer Fire Company Chief Corey Comperatore, 50, was killed by one of Crooks' bullets at the rally.
Attendees James Copenhaver, 74, and David Dutch, 57, were critically injured and remain stable.
Trump was hit in the ear before ducking from the bullets.