WASHINGTON D.C. — Cole Allen charged a security checkpoint outside the White House Correspondents' Dinner at the Washington Hilton Hotel on Saturday armed with a shotgun, a handgun and knives, acting Attorney General Todd Blanche said. President Trump and other administration officials were quickly escorted out of the event, which was canceled shortly thereafter.

Allen wrote a manifesto stating he planned to target Trump administration officials prioritized from highest-ranking to lowest. The manifesto stated law enforcement, hotel employees and guests were not his intended targets but he would still attack them to get to the administration. Allen's brother called police in Connecticut to alert them about the manifesto email, according to law enforcement sources.

The writings sent to family members did not specifically mention the dinner. Authorities found other writings at Allen's home in Torrance, California, and in his 10th-floor hotel room at the Washington Hilton.

In the manifesto, Allen apologized to his family and to colleagues and students whom he had told he had a personal emergency. "Hello everybody! So I may have given a lot of people a surprise today," he wrote. "I apologize to my parents for saying I had an interview without specifying it was for 'Most Wanted.'" He said he expected that by the time anyone read the email, he probably would need emergency care, referring to any potential injuries as "self-inflicted status."

Allen also wrote: "Ok now that all the sappy stuff is done, what the hell is the Secret Service doing?" and "No damn security." He said that if he had been an Iranian agent, he could have brought in a machine gun, which he referred to as "Ma Deuce," and no one would have noticed.

He wrote that he would not target Secret Service, Capitol Police or National Guard troops unless necessary, and added: "In order to minimize casualties, I will also be using buckshot rather than slugs (less penetration through walls)." A Secret Service officer who was shot was wearing a bulletproof vest and was released from the hospital Sunday.

Allen addressed his own background in the writings. "As a half-black, half-white person, you shouldn't be the one doing this," he wrote, before adding: "Rebuttal: I don't see anyone else picking up the slack." He also wrote, "Turning the other cheek is for when you yourself are oppressed," and, "I don't expect forgiveness, but if I could have seen any other way to get this close, I would have taken it."

After the attempted attack, Allen's sister told investigators that he often talked about doing "something" to fix perceived problems in society. Authorities found anti-Trump and anti-Christian rhetoric on his social media accounts. Family members told investigators that he regularly went to the shooting range to train with his guns and said he was part of a group called "The Wide Awakes" and had attended a "No Kings" protest in California. He legally owned two guns, one of which was used in the shooting at the hotel.