WASHINGTON, D.C. — Cole Tomas Allen, a teacher and engineer from Torrance, California, charged a security checkpoint and fired a shotgun on the second floor of the Washington Hilton on Saturday, one floor above a ballroom where President Donald Trump was attending a White House Correspondents' Association black-tie event, according to law enforcement officials. Allen made his first federal court appearance on Monday and was charged with attempted assassination of the president, interstate transportation of a firearm and ammunition with intent to commit a felony, and discharge of a firearm during a violent crime.

A total of six shots were fired when Allen ran past magnetometers, according to a law enforcement source: one by Allen and five by a Secret Service Uniformed Division officer. Investigators believe the shot fired by Allen struck the officer's ballistic vest, hitting the cellphone in its pocket, and have determined that the officer was not struck by friendly fire. Officials are conducting ballistics testing to confirm whether Allen's shot hit the officer.

The officer was not seriously injured, was taken to a hospital and released over the weekend. Officials estimated that Allen was running at about 9 miles per hour when he discharged the shotgun. Allen tripped and fell during the incident, and officers restraining him stripped him of his weapons and shirt to check for explosives. He was arrested at the scene and was not wounded.

In the ballroom one floor below, Trump, first lady Melania Trump, the majority of the Cabinet and their spouses, and more than 2,000 guests were told to take cover, according to officials. Secret Service agents escorted the president and first lady away.

Allen traveled to Washington by train from California carrying two firearms and several knives, and booked a hotel room, using an unguarded back stairwell from his room 10 floors up to reach the checkpoint. Prosecutors filed selfies Allen took in his hotel room on Saturday night before the attack, showing him in front of a mirror wearing black clothing and a red necktie, a small leather bag, a shoulder holster, a sheathed knife, pliers, and wire cutters. Charging documents include an email from Allen to family members stating he wished to target administration officials prioritized from highest ranking to lowest. In a note sent to family minutes before he charged the checkpoint, Allen wrote that he believed it was his duty to target Trump administration officials, apologized, and said he did not expect forgiveness.

Allen appeared in federal court wearing a blue jumpsuit, flanked by U.S. Marshals, during a brief initial hearing on Monday and did not enter a plea. After his federal public defenders said in an emergency filing that jail officials had not allowed confidential communication with him, U.S. District Court Magistrate Judge Matthew Sharbaugh ordered the city's corrections department to allow unrestricted legal visits. Investigators are analyzing devices recovered from Allen, including desktop and laptop computers from his California home and his phone, laptop and hard drives recovered from his guest room at the hotel.