Probe into Donald Trump assassination attempt makes halting progress as he reveals VP pick on first day of GOP convention

Donald Trump was formally nominated as his party’s presidential candidate as Republicans kicked off their national convention Monday under heightened security concerns and an ongoing investigation into the attempt on his life during a weekend campaign rally in Western Pennsylvania.

The former president pledged resilience in his first media interviews following the attempted assassination Saturday at a fairgrounds in Butler, Pa. He said his brush with death had prompted him to “throw out” the speech that he’d planned to deliver to party delegates at the Milwaukee convention later this week.

Instead, he told the New York Post, he was drafting a new address that he hoped would “unite our country” but added: “I don’t know if that’s possible.”

Meanwhile, federal authorities reported only halting progress Monday in their efforts to determine what motivated Thomas Matthew Crooks, the 20-year-old Allegheny County man they’ve identified as Trump’s would-be assassin, as finger-pointing and recriminations continued surrounding the failure of security protocols that allowed him to get so close to the rally stage.

» READ MORE: As it happened: Trump picks JD Vance as running mate as RNC begins; federal case against former president is dismissed

Leaders of three congressional committees announced plans to hold hearings, with the House Committee on Oversight announcing it would kick things off with testimony next week from Kimberly Cheatle, the director of the U.S. Secret Service.

Cheatle defended her agency’s handling of the Butler rally in a statement — her first since the thwarted attempt on Trump’s life. She also expressed confidence in the Secret Service’s RNC security plans.

“The Secret Service is working with all involved federal, state, and local agencies to understand what happened, how it happened and how we can prevent an incident like this from ever taking place again,” Cheatle said.

The day also delivered Trump a series of significant wins. In addition to receiving the official GOP nomination during a roll-call vote from the convention floor, he revealed his pick for vice president — U.S. Sen. JD Vance of Ohio — and scored a significant legal victory in one of the three remaining criminal cases pending against him.

» READ MORE: U.S. reps from Pa. weigh in on House investigation into Trump assassination attempt

A federal judge in Florida dismissed charges that Trump had mishandled classified documents after leaving the White House, ruling that Special Counsel Jack Smith, whose office had brought the case, had been improperly appointed and was, therefore, illegally prosecuting the case.

The decision, which broke with years of precedent, drew scrutiny from legal experts. Smith’s office, through a spokesperson, vowed to appeal.

» READ MORE: Judge dismisses Donald Trump’s charges over alleged mishandling of classified documents

But while Trump had pledged unity in the interviews he gave conservative media just hours before, he greeted news of his legal reprieve with a post on his social media platform, Truth Social, denouncing what he described as a Democratic witch hunt against him.

The FBI said Monday it had conducted nearly 100 interviews of law enforcement officials, rally attendees, and those who knew Crooks over the last two days since his attack on Trump, which also killed one spectator and left two others seriously wounded. But with the gunman dead and unable to provide answers, officials were seemingly no closer to explaining what prompted his actions.

Crooks’ parents are cooperating with the investigation. And agents gained access Monday to data on his phone, though it yielded few clues into his motivations, they said. Investigators have been stymied in their search for a motive by Crooks’ relative lack of social media presence and absence of any clear political leanings.

A registered Republican, he’d previously donated to a progressive political action committee. Former classmates at Bethel Park High School, the suburb of Pittsburgh where Crooks grew up, have offered conflicting depictions, with some describing him as a quiet victim of bullying and others recalling him as an engaged student unafraid to embrace conservative politics.

» READ MORE: What Thomas Matthew Crooks’ ex-classmates and employer have said about the Trump shooting suspect

Law enforcement sources, speaking on the condition of anonymity to protect their investigation, told the Washington Post on Monday they’d determined the gun Crooks used Saturday had been legally purchased by his father 11 years ago. Crooks bought 50 rounds of ammunition at a local gun store the morning of the rally, they said.

Kevin Rojek, FBI special agent in charge in Pittsburgh, said investigators do not yet know if Crooks took the gun without his father’s permission.

Investigators, who are treating the incident as an act of domestic terrorism, believe Crooks acted alone. And Butler County District Attorney Richard A. Goldinger said Monday that in light of Crooks’ death at the hands of the Secret Service, he did not anticipate filing criminal charges in connection with the attack.

Meanwhile, attention remained focused on the Secret Service’s apparent failure to secure the rally site.

The agency told CNN that it did not sweep the agricultural tool manufacturing plant from which Crooks took up his rooftop position and fired the shots that grazed Trump’s ear, killed one man, and seriously wounded two other spectators. Instead, it said, it had relied on local law enforcement to secure the building.

But Bob Dandoy, mayor of the City of Butler, said in an interview with The Inquirer that just a small number of city police had helped man the rally grounds. They were responsible, he said, for securing the hospital after Trump and victims were transported there.

He said that the city and township of Butler each have their own police forces, and that he was not sure which was the main source of support to the Secret Service on Saturday.

» READ MORE: In sleepy Butler, Pa., emails of praise and threats are inundating city workers: ‘You failed’

The Pennsylvania State Police maintained, meanwhile, that it was not responsible for the area where the building was located and that it “delivered all resources that the United States Secret Service requested,” helping secure the inside of the perimeter.

No matter who was responsible for the building, signs of trouble emerged minutes before shots rang out.

Several rally-goers have reported to local authorities that they saw Crooks acting suspiciously and pacing near magnetometers earlier in the day, according to a law enforcement official who spoke to the Associated Press on the condition of anonymity.

Video posted to social media late Sunday showed other attendees outside the security perimeter waving law enforcement toward Crooks’ position on the rooftop minutes before he opened fire. At one point, an officer can be seen walking near the building as the gunman takes his position near the roof’s peak. But it was not clear whether he heard the people in the audience trying to direct his attention to the threat.

A Butler Township police officer who was dispatched to investigate briefly encountered Crooks before shots rang out, but was forced to drop back down to safety when the gunman pointed his rifle at him, Butler County Sheriff Michael Slupe said.

“I think all law enforcement on site did everything that they could, especially the local law enforcement,” Slupe told the Associated Press. “I hope they’re not made the scapegoat.”

Butler Township Manager Tom Knight said the officer had lost his grip — and was not retreating. He fell eight feet to the ground. “He was literally dangling from the edge of a building and took the defensive position he needed to at the time,” Knight said.

Nathan Stedman, a Butler resident who was among those outside the fairgrounds who spotted Crooks before the shooting and attempted to alert law enforcement, can be heard in several videos from the scene shouting: “He’s got a gun!”

He told the New York Times on Monday that after he shouted, he witnessed Crooks roll over onto his back and fire two shots toward the other end of the building. Another flurry of gunshots erupted later seconds later, Stedman said. Homeland Security Secretary Alejandro N. Mayorkas described those events as a “failure” of security in an interview with CNN.

“An incident like this cannot happen,” he said.

But those lingering questions and the heightened focus on security did not appear to have dampened the celebratory mood among GOP delegates as they gathered in Milwaukee for the first day of their party’s nominating convention.

Though they endured hourlong wait times in screening checkpoint lines for secured areas and were limited to carrying only what they could fit into convention-issued small, clear tote bags, Secret Service officials said those measures had been planned before the attempt on Trump’s life.

Still, delegates eagerly filed into the convention hall to cast their roll call votes that formally named Trump their nominee and to celebrate the unveiling of Vance as his vice presidential pick.

» READ MORE: Donald Trump’s vice presidential choice takes on an additional significance in the aftermath of an attempted assassination

Earlier in the day, Pennsylvania’s delegates gathered at a state delegation breakfast in Waukesha, a suburb of Milwaukee, under a renewed spotlight in light of the weekend’s events in Butler.

“Because of what happened Saturday evening the eyes of the world are on us,” delegate chair Jim Worthington said.

He recounted the defiant image of former President Donald Trump, fist raised after he was shot, walking off stage.

“It is now our turn to do the same thing, because the future of America is dependent upon Pennsylvania,” Worthington said.

» READ MORE: Pa. delegates are in the spotlight as RNC kicks off after Trump assassination attempt

Other speakers called for less violent rhetoric in politics.

“Where we go from here is the question,” U.S. Rep. Dan Meuser (R., Pa.) said at the breakfast. “What do we do? There’s talk of unity. Is this a clarifying moment of unity? Let’s do our best to make it that.”

Then, in a jab at his rival party, Meuser added: “But did you see by any chance the release that Democrats put out on our platform? It was full of hate.”

Staff writers Rob Tornoe, Ryan W. Briggs, and Max Marin contributed to this article, which also contains information from the Associated Press.