But at the joint hearing of the Judiciary and Homeland Security committees, Rowe also highlighted the missteps of local law enforcement on July 13, when the former president was shot.
Rowe testified that Secret Service agents on Trump's security detail, as well as snipers on duty, were not told that the shooter, Thomas Matthew Crooks, was positioned on a nearby roof with a rifle and only learned of his presence after he started shooting.
Federal investigators are looking into a YouTube account possibly connected to Crooks in which the user espoused political violence as well as antisemitic and anti-immigration themes, a source familiar with the investigation tells CNN. Deputy FBI Director Paul Abbate described the account but did not reveal the platform at the hearing.
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The hearing was the fourth such one held on Capitol Hill since the assassination attempt, and though it grew testy at times, especially during some exchanges with Republican senators, lawmakers appeared largely satisfied with the information provided by Rowe and Abbate during their more than three hours of testimony.
Overall, it stood in stark contrast with a House hearing held last week in which lawmakers grilled then-Secret Service Director Kimberly Cheatle over what went wrong earlier this month, with several members demanding she resign over the lapses. A day later, she did just that.
Here are the takeaways from Tuesday's joint hearing:
'Siloed' information about Crooks' presence
During Tuesday's hearing, Rowe highlighted the failures of communications during the rally, in Butler, saying that information about Crooks was "siloed" and "stuck" in local law enforcement channels.
"The only thing we had was that locals were working an issue at the three o'clock - which would have been the former president's right-hand side - which is where the shot came," Rowe said. "Nothing about man on the roof, nothing about man with a gun. None of that information ever made it over our net."
Homeland Security Committee Chairman Gary Peters said that local law enforcement has claimed they were "only able to call in to a state command center" and not able to easily communicate threats to the Secret Service.
But Peters also noted that Abbate testified during the hearing that "there was about 30 seconds between when the local law enforcement reported that there was a man on the roof with a gun" and when the shooter began firing.
"If it's communicated directly to a counter-sniper team, would that be enough time to react prior to the firing of those shots?" Peters asked.
"If we'd had that information, they would have been able to address it more quickly," Rowe replied. "It appears that that information was stuck or siloed in that local channel."
"It is troubling to me that we did not get that information as quickly as we should have," he said. "We didn't know that there was this incident going on."
Crooks was killed within 15.5 seconds of the first shot, Rowe said.
Counter-drone system could have prevented the attack
Rowe confirmed that the reason a counter-drone system was not deployed at the Butler rally earlier in the day was because of connectivity issues.
"On this day in particular, because of the connectivity challenge ... there was a delay," he said. Crooks flew his own drone around the area two hours before Trump took the stage.
The issue has "cost me a lot of sleep," Rowe said. "What if we would have geolocated him because that counter (unmanned aircraft system) platform would have been up."
Rowe said that had the system been up, law enforcement may have been able to see Crooks' use of his own drone and approached him well before the shooting.
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Moving forward, Rowe said, his agency will use drones to help better secure future events.
"It is clear to me that other protective enhancements could have strengthened our security at the Butler event," he told lawmakers. "As such, I have directed the expanded use of unmanned aerial systems at protective sites to help detect threats on roofs and other elevated threats."
The acting director also said that the Secret Service will now work with the Department of Homeland Security to set up their own, private connection and not rely on public domain connections.
The rally also did not deploy a Secret Service counter surveillance unit that would be dedicated to observing and tracking suspicious people like Crooks, according to multiple sources familiar with the operation.
A law enforcement source told CNN the counter surveillance units were not requested as part of the plan put together by the Secret Service. The source said the units are not typically used for protection of former presidents.
Rowe points fingers at local law enforcement
As lawmakers pressed Rowe for answers on what went wrong earlier this month, the interim Secret Service director sought to shirk some of the responsibility for the security lapses, partially blaming the issues on the local law enforcement officers with whom they were working.
Moving forward, Rowe told the committees, his agency will avoid assuming local law enforcement agencies are fully capable of fulfilling their role in protecting an event.
"We assumed that the state and locals had it," Rowe said of the area where Crooks climbed up the side of a building near the rally with his rifle.
"We made an assumption," he said, explaining that the Secret Service believed there would be sufficient eyes to cover the area and that local law enforcement would have a counter sniper in the AGR building where Crooks took his position.
Rowe told the lawmakers that local law enforcement was positioned in a nearby building and should have had a clear line of sight of Crooks on the roof.
"I cannot understand why there was not better coverage or at least somebody looking at that roofline when that's where they were posted," Rowe said, noting that a local sniper team could have looked from their post and seen the would-be assassin.
"Looking left, why was the assailant not seen?" Rowe asked of the local team, as he showed lawmakers photographs of the roofs snipers were positioned on.
"I'm not saying that they should have neutralized him, but if they'd have held their post and looked left maybe..." Rowe said later, though he was quickly cut off by an unrelated comment.
Shouting matches over firings and Biden v. Trump resources
Several senators lambasted Rowe for not firing any members in his agency and over the amount of security provided to former President Trump compared to President Joe Biden.
In one such exchange, Rowe loudly objected to Sen. Josh Hawley's persistent questions about why individuals weren't fired in recent weeks.
"I will not rush to judgment. People will be held accountable," Rowe said, adding that investigations into the failures that day are ongoing.
The Missouri Republican responded: "Is it not prima facie that somebody has failed? The former president was shot."
"Sir, this could have been our Texas School Book Depository," Rowe responded, referring to the 1963 assassination of President John F. Kennedy in Dallas. "I have lost sleep over that for the last 17 days, just like you have."
"Then fire somebody," Hawley shouted, to which Rowe replied: "We have to be able to have a proper investigation into this."
At another point during Tuesday's hearing, Republican Sen. Ted Cruz repeatedly pressed Rowe on why Trump doesn't receive the same security level as Biden.
"There is a difference between the sitting president of the United States," Rowe said.
"Then what's the difference," Cruz yelled, cutting Rowe off.
"The difference - national command authority to launch a nuclear strike, sir," Rowe responded. "There are other assets that travel with the president that the former president will not get."
Crooks' online presence
Investigators have uncovered a social media account with posts espousing political violence that may be connected to the would-be Trump assassin, Abbate said.
Officials have repeatedly said that they have struggled to understand what the 20-year-old shooter's motive was, and that they are combing his online presence for more information.
"Something just very recently uncovered that I want to share is a social media account, which is believed to be associated with this with the shooter - in about the 2019, 2020 timeframe," Abbate said.
On that account, "there were over 700 comments," Abbate said, which, "if ultimately attributable to the shooter, appear to reflect antisemitic and anti-immigration themes, to espouse political violence, and are described as extreme in nature."
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CNN has learned the account is on the YouTube platform.
A separate account on the platform Gab - which was made years earlier - appears to have "differing points of view," Abbate added.
Gab CEO Andrew Tobra revealed last week that the would-be assassin may have had an account on the site, which is an alternative social media network popular with conservatives, the alt-right and some extremists. Tobra claimed that the account in question was "pro-Biden."
The Gab account has also not been conclusively connected to Crooks.
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