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.