Ronald Rowe Jr. also testified that he recently visited the shooting site and laid down on the roof of the building where shots were fired in order to evaluate the gunman’s line of sight during the July 13 shooting in Butler, Pennsylvania.

“What I saw made me ashamed. As a career law enforcement officer and a 25-year Secret Service veteran, I cannot defend why that roof was not better secured,” he said.

The testimony was the most detailed catalog to date by the Secret Service of law enforcement failings and miscommunications, with Rowe accepting blame for his own agency’s mistakes while also pointedly criticizing local law enforcement for communication breakdowns that resulted in his agency not receiving information that a gunman, later identified as 20-year-old Thomas Matthew Crooks, had been seen on the roof of a building less than 150 yards (135 meters) from the rally stage where Trump was speaking.

“Neither the Secret Service counter sniper teams nor members of the former president’s security detail had any knowledge that there was a man on the roof of the building with a firearm,” Rowe said. “It is my understanding those personnel were not aware the assailant had a firearm until they heard gunshots.”

He said that the shooting amounted to a “failure on multiple levels,” including a failure of imagination and a “failure to challenge our assumptions.”

“We assumed that the state and locals had it,” Rowe said. “We made an assumption that there was going to be uniformed presence out there, that there would be sufficient eyes to cover that, that there was going to be counter-sniper teams” in the building from whose roof Crooks fired shots.

“And I can assure you,” Rowe added, “that we’re not going to make that mistake again.”

He said he had implemented multiple reforms since taking over as acting director last week, including mandating that every event security plan is vetted by multiple experienced supervisors before being implemented, expanding the use of aerial drones to improve visibility of roofs, dedicating more resources to improve communications at events where the Secret Service is operating. He said he’s also directed that federal and local counter snipers work together on roofs.

Trump, the 2024 Republican presidential nominee, was struck in the ear by a bullet or a bullet fragment in the assassination attempt, one rallygoer was killed and two others were injured before the gunman was killed by a Secret Service counter-sniper.

The blunt and at times emotional testimony Tuesday, featuring combative exchanges with lawmakers, ensured that an already simmering blame game between federal and local authorities will continue. It also suggested that Rowe, with ready and generally detailed answers, was determined to strike a different posture than that of his predecessor, Kimberly Cheatle, who resigned last week after facing intense criticism from lawmakers from both major political parties following responses at a congressional hearing that were seen as evasive and lacking in specifics.

Tuesday’s hearing before the Senate Judiciary and Homeland Security committees was the latest in a series of congressional sessions dedicated to the law enforcement lapses and missed communications that preceded the shooting.

Local law enforcement officers had first observed a suspicious-looking man at the rally site more than an hour before the event and circulated that information, including photographs of a man who turned out to be Crooks. But the officers ultimately lost track of Crooks, who was able to scale the roof of a building at AGR International Inc., a supplier of automation equipment for the glass and plastic packaging industry, and fire an estimated eight shots with an AR-15-style rife.

Shortly before the shooting, a local officer climbed up to the roof to investigate. Crooks turned and pointed his rifle at the officer, who retreated.

Even though text messages among local snipers revealed anxiety about the man, Rowe said the only thing the Secret Service knew at the time of the shooting was that law enforcement was contending with a suspicious-looking man.

“No information regarding a weapon on a roof was ever passed to our personnel,” Rowe said. At another point, he noted, “It is troubling to me that we did not get that information as quickly as we should have. We didn’t know that there was this incident going on.”

But Rowe’s willingness to assign blame to local law enforcement opened him up to harsh criticism from Senate Republicans, who saw him as failing to take sufficient responsibility.

“Isn’t the fact that a former president was shot, that a good American is dead, that other Americans were critically wounded — isn’t that enough mission failure for you to say to the person who decided that that building should not be in the security perimeter, probably ought to be stepped down?” said Sen. Josh Hawley, a Missouri Republican.

Rowe, raising his voice, responded that he has “lost sleep over this for the last 17 days” and that he would not be rushed “to judgment” by Congress. He assured lawmakers that “people will be held accountable.”

Sen. Lindsey Graham, the top Republican on the Senate Judiciary Committee, said if something like this happened in the military, “a lot of people would be fired. And if a lot of people are not fired, the system failed yet again.”

He added: “Nothing’s going to change until somebody loses their job.”

The FBI, meanwhile, disclosed new details about Crooks, with Deputy Director Paul Abbate saying a social media account believed to be associated with the gunman suspected in the assassination attempt espoused political violence and included antisemitic and anti-immigrant sentiment. The posts were from the 2019-2020 timeframe, when Crooks would have been in high school.

Abbate did not identify the social media platform, saying investigators were still trying to definitively determine that it belonged to Crooks. However, he indicated that it was separate from an account on a different platform called Gab that was active in 2021.

The chief executive of Gab posted on X, formerly known as Twitter, during the Senate hearing that Crooks’s presence on that platform was consistent with being “pro-Biden and in particular pro-Biden’s immigration policy.”

On Monday, the FBI revealed that Crooks had looked online for information about mass shootings, power plants, improvised explosive devices and the May assassination attempt of the Slovakian prime minister Robert Fico.

The FBI also said that Trump has agreed to be interviewed by agents as a crime victim.