Federal prosecutors told a judge Wednesday about an accused gunman’s planning before attempting to breach a Washington ballroom Saturday night in a failed attempt to assassinate President Donald Trump and top administration officials.

In a memorandum requesting 31-year-old Cole Allen be kept in custody before his eventual trial, U.S. Attorney for the District of Columbia Jeanine Pirro wrote that his actions before the annual White House Correspondents’ Association dinner “were premeditated, violent, and calculated to cause death.”

The memo to the U.S. District Court for the District of Columbia argued that, based on evidence it spells out in detail, “there is no condition or combination of conditions” that should lead to his release before a trial.

“Had the defendant successfully made it into the ballroom, he not only could have killed or injured dozens of people, but he could have destabilized the entire federal government, given the number of high-ranking government officials present,” the memo states. “The defendant sought to express his political opinions through violence.”

The document includes selfies the alleged gunmen took in his room at the Washington Hilton and information investigators found about his rush through a security checkpoint and attempt to breach the massive ballroom.

Around 2,600 guests, Trump and a list of top administration officials had gathered there. Allen was pictured in a mirror wearing a black button-down shirt and black pants, along with a red necktie.

The filing also contains photos of the weapons prosecutors say he was carrying: a Mossberg 12-gauge pump-action shotgun, a Rock Island Armory 1911 .38-caliber pistol, ammunition and knives. The Justice Department told the court Allen was detained carrying “enough ammunition to take dozens of lives.”

An ongoing investigation already has “yielded significant evidence of the defendant’s extensive planning and preparation for his attack,” the prosecutor told the court.

Allen appears to have begun planning for his attack earlier this month, using his cellphone on April 6 to search for information about the White House Correspondents’ Association-sponsored gala, according to the filing. The same day, he received a confirmation email for a two-night stay at the Washington Hilton, the longtime host of the event.

After traveling from Los Angeles to Washington via Amtrak, Allen checked into the hotel on Friday afternoon, around 3:15 p.m., according to the filing. In a postscript to a letter he emailed to family and colleagues, Allen mocked the security footprint inside the Hilton and appeared to refer to a M2 .50-caliber Browning heavy machine gun.

“The defendant ‘rant[ed] and described what he viewed as deficiencies in the security at the hotel. He wrote that he ‘walk[ed] in with multiple weapons and not a single person there [at the hotel] considers the possibility that I could be a threat.’ The defendant went on to complain that “if I was an Iranian agent, instead of an American citizen, I could have brought a damn Ma Deuce2 in here and no one would have noticed shit,’” he wrote, according to the memo.

He signed that letter, which he had pre-scheduled to send at 8:30 p.m. Eastern time on Saturday “Cole ‘coldForce’ ‘Friendly Federal Assassin’ Allen,” the memo states.

The memo states that Allen left his room several times on Saturday evening, including a period of around 20 minutes that began at 6:26 p.m. Eastern time, long after dinner guests and administration officials, clad in formal attire, had begun milling around the sprawling Hilton complex. Allen allegedly used his phone to search for Trump’s Saturday schedule, which had been publicly released by the White House.

Once back in his room, Allen took the selfie photographs and left for the last time around 8:13 p.m. The prosecutor’s filing did not lay out Allen’s path to the security checkpoint on the Hilton’s terrace level, one level above the ballroom. Nor does it state how he accessed the terrace level — guests had been required to show their official ticket at the top of an escalator and an outside entrance. But it does state that between the time he left his room and charged the checkpoint, he used his phone to access a media outlet’s live stream of the dinner.

The document also features Allen’s own words, from the emails he sent, about why he allegedly wanted to assassinate Trump and administration officials.

“I apologize to everyone who was abused and/or murdered before this, to all those who suffered before I was able to attempt this, to all who may still suffer after, regardless of my success or failure. I don’t expect forgiveness, but if I could have seen any other way to get this close, I would have taken it,” he wrote. “Again, my sincere apologies.

“On to why I did any of this: I am a citizen of the United States of America. What my representatives do reflects on me,” he wrote, according to the memo. “And I am no longer willing to permit a pedophile, rapist, and traitor to coat my hands with his crimes.”

In an interview with CBS’ “60 Minutes” that aired Sunday night, Trump denied those allegations, calling a female interviewer a “disgrace” for reading that part of Allen’s writings.

The alleged attempted assassin ended his emailed letter contending he felt “awful” about what he would attempt to do just moments later. His self-described motivation was that he “experience[d] rage thinking about everything this administration has done,” adding: “Can’t really recommend it! Stay in school, kids.”