FBI Director Kash Patel delivered defiant testimony before the Senate Judiciary Committee on Tuesday, amid increasing scrutiny of his handling of the investigation into conservative youth leader Charlie Kirk’s assassination in Utah.

Patel, sporting a red tie with the Liverpool FC logo, repeatedly clashed with Democrats for more than three hours, shrugging off their suggestions that he mishandled the case and has politicised the FBI.

He also revealed new details about the Kirk assassination, the FBI’s handling of the Jeffrey Epstein case and the Trump administration’s plans to clamp down on crime in US cities.

He will go before the House Judiciary Commitee on Wednesday.

Here’s what we know.

Patel’s appearance on Capitol Hill came as Democrats and other detractors have criticised the way he and the FBI have managed the probe into Kirk’s killing – in particular an inaccurate social media post that a suspect had been apprehended. The FBI later said two people had been questioned and released.

According to several news outlets, that criticism has led to growing exasperation from within the Trump administration.

Ahead of the hearing, Patel took the unusual step of twice appearing on Fox News, defending his handling of the case and detailing “shocking” evidence that he says the FBI has uncovered as a result of its aggressive pursuit of the suspect.

He also defended his initial social media post, noting that he could have “worded it a little better in the heat of the moment”.

“But do I regret putting it out? Absolutely not,” he said.

In front of the committee, Patel argued the suspect in the Kirk assassination was taken into custody just hours after the FBI released new images and video.

“That is the FBI working with the public as a promise to being transparent and providing critical information,” he said.

Trump has so far stood by Patel, telling reporters at the White House that he has “confidence in everyone in the administration”.

Patel also sought tamp down on criticism of the administration’s handling of the Epstein case, telling the committee the agency has “no credible information” that the late financier and convicted sex offender trafficked minors to others.

The investigation has long been plagued by theories that Epstein had a “client list” of high-profile figures who participated in his crimes.

Patel was later pressed for more answers on the case by California Democrat Adam Schiff, and seemed to contradict himself when he answered that he “never said Jeffrey Epstein didn’t traffic anyone else”.

Democrats on the committee sought to paint a picture of chaos and incompetence at the FBI, pointing to the agency’s handling of Kirk’s assassination and former agents claiming they were fired for political reasons.

The committee’s top Democrat, Dick Durbin of Illinois, described Patel as the “most partisan FBI director ever” and accused him of overseeing a “disasterous brain drain” since taking the office.

But Patel showed no signs of backing down, ending his opening remarks with the words “bring it on” and speaking over Democrats on the committee.

In one particularly fiery exchange, Patel called Schiff a “political buffoon” as the California Democrat questioned him about Jeffrey Epstein and the transfer of his associate Ghislaine Maxwell to a minimum-security prison in Texas.

“I’m not giving it to you,” Patel says to Schiff, before accusing him of being a liar. “You are the biggest fraud to sit on the United States Senate.”

The pair’s acrimonious relationship dates back to when Schiff was a House member and chair of the House Intelligence Committee, overseeing the probe into Russian interference in the 2016 presidential election. Patel served as a House Intelligence staffer who sought to discredit the investigation.

In another clash, this time with New York Senator Corey Booker – who told the FBI director he was “failing as a leader” – Patel shot back: “I am not afraid of you!”

The spats partly overshadowed Patel’s revelations about various investigations, which included a remark that “a lot more” than 20 people involved in a Discord chat with alleged Kirk assassin Tyler Robinson will be interrogated by the FBI.

While he did not reveal specific operational plans, Patel hinted at the next US cities that could face a surge in federal resources or National Guard deployments to fight crime as part of the Trump administration’s wider crackdown across the country.

National Guard troops and federal law enforcement agencies have already been deployed to Washington DC, and earlier this week Trump announced a similar deployment to Memphis, Tennessee.

In response to a question by Florida Republican Ashley Moody, Patel listed a number of American cities that might be next.

“We did it in DC. We’re doing it in Memphis. We’re going to Chicago, Miami, St Louis – so many other cities across the country,” he said.

On Monday, Trump similarly said that he plans to “take care” of other cities the administration believes are crime-ridden “step by step”, adding that he still has his sight set on Chicago and St Louis, Missouri.

The president has also previously mentioned New Orleans – where the idea was welcomed by Louisiana governor Jeff Landry – and Baltimore.

Legal experts have questioned the legality of using troops in US cities, and earlier in September a federal judge in California ruled that Trump’s deployment of troops to quell unrest in Los Angeles this summer was illegal.

That ruling, however, does not apply to other cities.