Trump told Fox News on Sunday that the suspect was "a sick guy" and that his family previously expressed concerns about him to law enforcement officials. The suspect, whom an official identified as Cole Tomas Allen of Torrance, California, was arrested at the scene of the event in Washington, D.C.
"When you read his manifesto, he hates Christians," Trump said on Fox News.
The manifesto was sent to Allen's family members shortly before the attack, a law enforcement official told Reuters. The suspect called himself the "Friendly Federal Assassin," the official said.
"Turning the other cheek when *someone else* is oppressed is not Christian behaviour; it is complicity in the oppressor's crimes," the manifesto read, according to the official.
Targets listed in the manifesto included administration officials - although not FBI Director Kash Patel - prioritised from highest-ranking to lowest, the official said.
The manifesto mocked the "insane" lack of security at the Washington Hilton, where the dinner was held, the official added.
"Like, the one thing that I immediately noticed walking into the hotel is the sense of arrogance," the manifesto's author reportedly wrote.
"I walk in with multiple weapons and not a single person there considers the possibility that I could be a threat."
Officials have said that the suspect fired a shotgun at a Secret Service agent at a security checkpoint in the Washington Hilton hotel before being tackled and arrested.
Trump, first lady Melania Trump, Vice President JD Vance and other cabinet officials were rushed out of the dinner as the incident unfolded. The Secret Service agent who was shot escaped serious injury because the bullet struck his protective vest, Trump said.
Trump, who had boycotted the media gala in the past, has requested that the dinner be rescheduled within 30 days, adding: "That was going to be an important event."
The suspect will be charged in federal court on Monday.
Saturday's incident came amid a rising tide of political violence in the United States in recent years. Conservative political activist Charlie Kirk was shot dead at a rally last September, just months after the June 2025 slaying of Democratic Minnesota state Representative Melissa Hortman and her husband and the wounding of a Minnesota state senator in June 2025.
A Reuters/Ipsos poll conducted in the days following Kirk's murder found that Americans believe that increasingly harsh rhetoric surrounding politics is encouraging violence in the US
Around the world, leaders condemned the attack and expressed relief that Trump and all present were safe. NATO leader Mark Rutte called it an attack "on our free and open societies" and leaders stressed violence had no place in a democracy.
A planned US visit by King Charles of Britain scheduled to start on Monday will proceed, Trump and British officials said.
Little was immediately known about the 31-year-old alleged shooter's background, but social media postings suggested he was a teacher in Torrance, near Los Angeles.
Washington Interim Police Chief Jeffery Carroll said the suspect was armed with a shotgun, a handgun and multiple knives.
The chaotic events from around 8.35pm local time raised fresh questions about the security of top US officials, many of whom were gathered in the hotel's expansive ballroom.
The dinner was attended by many members of Trump's cabinet and other senior administration officials amid heavy security. It was the first time Trump attended the event as president, having boycotted it in previous years.
The site of the dinner was the scene of an attempt on the life of President Ronald Reagan, who was shot and wounded by a would-be assassin outside the hotel in 1981.
