FBI agents entered the Bethel Park, Pennsylvania, home of Thomas Crooks, who allegedly attempted to assassinate Donald Trump. Crooks, 20, is accused of firing an AR-15 at Trump during a rally in Butler on Saturday evening, missing Trump but hitting three other victims — one fatally.

“The FBI continues to investigate the shooting incident at the July 13 rally in Butler, Pennsylvania, as an assassination attempt on former President Donald Trump and as potential domestic terrorism,” the FBI told Fox News‘ David Spunt. “The investigation is still in the early stages and the FBI is providing the following updates: FBI technical specialists successfully gained access to Thomas Matthew Crooks’ phone, and they continue to analyze his electronic devices. The search of the subject’s residence and vehicle are complete.”

The FBI reported that it has “conducted nearly 100 interviews of law enforcement personnel, event attendees, and other witnesses,” and the agency’s “work continues.”

Photos from Reuters show two FBI agents entering and exiting Crooks’ home on Monday morning. Roads leading to Crooks’ residence have been taped off since late Friday after the shooting.

“We have a 24/7 command post in Pittsburgh as well as here at FBI headquarters, and we are dedicating every resource that we have at our disposal,” said Robert Wells, assistant director of the FBI’s Counterterrorism Division. “Our number one goal here is to identify the motive of the subject and determine whether he had any other associates or anyone else that was involved at this point.”

The FBI is investigating Crooks’ actions as an assassination attempt. The 20-year-old allegedly shot at rally-goers from a rooftop about 160 yards from where Trump was speaking. Crooks killed 50-year-old Corey Comperatore, a former fire chief of Buffalo Township, and injured two others, David Dutch, 57, and James Copenhaver, 74. Secret Service agents returned fire, killing Crooks on the rooftop.

Crooks had been a member of the Clairton Sportsmen’s Club in nearby Clairton for at least a year. The club’s attorney, Rob Bootay, said in a statement to Fox News, “Beyond that, the Club is unable to make any additional commentary in relation to this matter in light of pending law enforcement investigations. Obviously, the Club fully admonishes the senseless act of violence that occurred yesterday. The Club also offers its sincerest condolences to the Comperatore family and extends prayers to all of those injured including the former President.”

Crooks graduated from Bethel Park High School in 2022 and was among about two dozen students who received a $500 “star award” from the National Math and Science Initiative. Though a registered Republican, he donated $15 to a Democratic, Chicago-based PAC in 2021.