According to initial reports from the probe into White House Correspondents' Dinner (WHCD) shooting suspect Cole Tomas Allen, the 31-year-old had planned to kill President Donald Trump and as many of his inner circle officials as possible.
However, law enforcement is still probing Allen's motive for infiltrating the WHCD (held at the Washington Hilton in Washington D.C.) on Saturday night (local time), trying to rush past security, and shooting a Secret Service agent before he was subdued.
Allen is still not cooperating with the investigation, Acting Attorney General Todd Blanche told NBC News.
The initial probe into the alleged WHCD shooter also involves "some writings" which are being reviewed, and indicate that the man travelled from his home in Torrance, California, to Chicago, and then to Washington by train over the past several days.
At Washington, he reportedly checked into the Washington Hilton hotel as a guest about 1-2 days before the high-profile dinner.
"We do believe he was a guest here at the hotel. We have secured a room here in the hotel, and again, we'll go through the appropriate procedures to determine what was inside there," said Jeffrey Carroll, interim chief of police for the Metropolitan Police Department.
Carroll added that the investigating authorities could not find any criminal records on Allen prior to his Saturday arrest, while Blanche noted that the two guns he had been carrying in the attack—a handgun and shotgun—had been purchased “within the last couple of years".
However, Blanche did not reveal further details about what kind of writings they were, or where they were found.
Trump has since termed the suspected shooter a "lone wolf whack job", indicating that he was likely acting alone, and has also called for the development of a new ballroom inside the White House to host such events with the "highest level security".
Cole Tomas Allen is expected to face preliminary charges of assaulting federal officers with a dangerous weapon and using a firearm during a crime of violence. He is expected to make his first appearance since the incident at a federal court in Washington on Monday, as per US Attorney Jeanine Pirro.
“(Allen) was intent on doing as much harm and as much damage as he could,” Pirro said, adding that she expected “many more charges” to be levied against him over the course of the probe.