The man accused of attempting to assassinate President Donald Trump during the White House Correspondents' Association Dinner on April 25 has officially been indicted by a grand jury, including on a new charge tied to the shooting.

The indictment was presented by the grand jury to Magistrate Judge Zia Faruqui.

Allen was indicted on four charges, three of which were announced on April 27, according to the indictment. 

The first three charges were attempting to assassinate the President of the United States, discharge of a firearm during a crime of violence and transporting a firearm across state lines.

The fourth charge, included in Tuesday's indictment, is assaulting a federal officer with a deadly weapon, the indictment says. 

"Today’s indictment underscores a simple truth: there is evidence this defendant intended to assassinate the president, and that he shot a U.S. Secret Service officer after he traversed the country with a cache of ammunition to accomplish his goals," U.S. Attorney Jeanine Pirro said in a statement. 

"I commend our law enforcement partners for their swift action to neutralize this threat and prevent the death of the President. The use of violence to register dissent is anti-democratic at its core. We will pursue the maximum punishment available under the law against anyone who travels to the District of Columbia to engage in such acts." 

When Allen was arrested, authorities said, he was in possession of a Mossberg shotgun with one spent cartridge in the barrel, a Rock Island Armory 1911 .38 caliber pistol, dozens of rounds of unspent 12-gauge shotgun ammunition and .38 caliber ammunition, two knives, four daggers, multiple sheaths, multiple holsters, needle nose pliers and wire cutters. 

Allen is due back in court on May 11. 

The Department of Justice (DOJ) says Allen descended from his 10th floor room at the Washington Hilton Hotel, where the White House Correspondents' Association Dinner was being held, and attempted to charge through a security checkpoint towards a ballroom where Trump, Vice President J.D. Vance and high-level cabinet members were seated. 

According to the DOJ, he fired one shot from a 12-gauge shotgun before falling to the ground and being apprehended. A small fragment of the buckshot round struck a Secret Service agent's vest, and he was briefly taken to the hospital for minor injuries. A Secret Service agent fired five shots at Allen, but did not strike him. 

Allen, 31, of Torrance, California, is accused of traveling by train from Los Angeles to Washington, D.C. over a period of three days, changing trains in Chicago.

Minutes before the attack, a pre-scheduled email from Allen was sent to his family and friends, explaining his actions, according to authorities.

He allegedly acknowledged that his mission would likely severely harm him at the least, but never stated that he was willing to die for his cause. His motivations were political, and he painted himself as a savior of the oppressed. 

Allen apologized profusely to family, friends and everyone he had come in contact with on his cross-country trek. He noted that there were certain people he hoped wouldn't be caught in the crossfire, and described himself as "friendly."