The shooter in the assassination attempt on former President Donald Trump flew a drone over a field adjacent to the grounds where the rally was held on July 13, three law enforcement sources familiar with the federal investigation into the shooting told CBS News on Saturday.

Investigators are still probing exactly when the shooter, identified as 20-year-old Thomas Matthew Crooks, flew the drone, the law enforcement officials said. They believe, however, that it was within days of the rally, though it remains unclear if he flew the drone hours or days prior to the event.

The Wall Street Journal was the first to report the use of the drone at the rally site.

CBS News previously reported that a drone was among the items recovered by investigators from the shooter's vehicle, according to three sources familiar with the U.S. Secret Service and FBI's joint briefing call with lawmakers on Wednesday. Two explosive devices, a tactical vest with plates in the front and back, and four magazines full of the same ammunition used in the attack were also found in the shooter's vehicle.

During the call, lawmakers also learned that the shooter sought out online photos of Butler Farm Show grounds – the site of the rally – and made searches about Allegheny Arms, a gun shop in Bethel Park, Pennsylvania, where he lived. They were also told that he visited the site of the rally at least once before the attack, sources told CBS News.

In the days after the rally was announced, he made internet searches related to Trump, President Biden, the former president's whereabouts on July 13 and the Democratic National Convention.

In a statement on Friday, Butler Farm Show said their involvement in the rally was simply renting the venue to the Trump campaign.

"The Butler Farm Show is fully cooperating with the FBI's ongoing investigation into this incident," they said in a statement, according to CBS Pittsburgh affiliate KDKA. "Due to the sensitive nature of the investigation, we have been unable to comment on the event until now."

Over the next few days, federal law enforcement will face questions from lawmakers about how the gunman was able to pull off the shooting.

Secret Service Director Kimberly Cheatle is scheduled to testify to the House Oversight Committee on Monday morning, while FBI Director Christopher Wray will testify before the House Judiciary Committee on Wednesday.

Meanwhile, Trump was back on the campaign trail after he was officially named the Republican Party's presidential candidate, appearing with his vice president pick, JD Vance, at a rally in Grand Rapids, Michigan on Saturday.

And in a statement posted to social media Saturday, Republican Rep. Ronny Jackson of Texas, a White House physician during the Trump administration, detailed Trump's wound and said that he has been providing ongoing medical treatment to Trump since the shooting took place. 

Trump sustained a 2 centimeter-wide wound to his right ear that "extended down to the cartilaginous surface of the ear," Jackson said. 

The swelling to Trump's ear has "since resolved," according to Jackson, and the "wound is preparing to granulate and heal properly." He disclosed that Trump still experiences "intermittent bleeding" that requires a dressing to be in place. According to Jackson, no sutures were required and Trump is "doing well." 

Gunman's high school says it has "no record" of him trying out for rifle team

The high school from which Crooks graduated said that it has "no record" of him attempting to join the school's rifle team. 

Former high school classmate Jameson Myers, a member of the Bethel Park High School's varsity rifle team, told CBS News that the gunman had tried out for the team freshman year but did not make the junior varsity roster and did not return to try out for the team in subsequent years. 

The Pennsylvania school refuted this claim in a fact sheet shared online.

"It has been reported that Thomas Crooks was a member of the Bethel Park High School rifle team or tried out for it but was dismissed due to poor performance or because the coach had character concerns," the school said. "Thomas Crooks was never a member of the school's rifle team and we have no record of him trying out. The coach does not recall meeting him. However, it is possible that Crooks informally attended a practice, took a shot, and never returned. We don't have any record of that happening."

The school also responded to statements that the gunman had been bullied while in high school. Some peers said that he had been an outcast. Myers, who shared the rifle team anecdote, remembered him as a "nice kid who never talked poorly of anyone" and said he was not picked on. 

"According to our records, Mr. Crooks excelled academically, regularly attended school, and had no disciplinary incidents, including those related to bullying or threats," the school said. "Mr. Crooks was known as a quiet, bright young man who generally got along with his teachers and classmates." 

An investigation into the gunman has turned up little in the way of political ideologies, federal investigators told members of Congress last week. Analysis of his devices showed that he had searched for both Trump and President Biden, and had looked up where Trump would speak from during his rally. He had also searched for the location of the Democratic National Convention. On the day of the attack, he searched for photos of the farm where Trump's rally was held and for a nearby gun shop that is cooperating with investigators, according to CBS News affiliate KDKA. 

Investigators have also conducted over 200 interviews, including with family, neighbors and coworkers. All interviewed family members said the gunman never discussed politics or ideology. 

In:
• Shooting
• Trump Rally
• Donald Trump

Pat Milton

Pat Milton, an award-winning journalist, is the senior producer of the CBS News Investigative Unit.