Washington — Accused White House Correspondents' Dinner attacker Cole Allen is now facing charges of assaulting a federal officer.

Allen was formally indicted Tuesday by a federal grand jury on four charges, including three counts that he was charged with through a criminal complaint last week — attempting to assassinate President Trump and two firearm charges — and a new count of assault on a federal law enforcement officer with a deadly weapon.

Federal prosecutors charged Allen in the hours after the attempted attack at the annual press gala in Washington, D.C., but had not presented the charges to a grand jury to secure an indictment until Tuesday. 

Prosecutors allege on April 25, Allen — armed with a shotgun, handgun and knives — attempted to break through a security checkpoint one story above the ballroom at the Washington Hilton, where Mr. Trump, top administration officials and members of the press corps were dining. 

The indictment also accuses Allen of assaulting a federal officer referred to as V.G. with a shotgun. Law enforcement officials have alleged that Allen shot at a uniformed Secret Service officer who was hit on his protective vest by buckshot. The officer was not seriously hurt.

Allen, 31, has not yet entered a plea and is set to be arraigned on May 11. Allen's legal team agreed that he will remain detained as pre-trial proceedings play out.

His case was assigned to U.S. District Judge Trevor McFadden, who was nominated to the post by Mr. Trump in 2017. 

On Monday, a federal magistrate judge in D.C. criticized Allen's treatment in the jail where he is being held, saying he was "very troubled" by the conditions he was subjected to. The magistrate, Zia Faruqui, apologized to the suspect for issues in his first week of detention. 

Lawyers for Allen said he was placed on suicide watch shortly after arriving at jail last week, meaning he was held in a padded cell with the lights on constantly and no access to a phone or tablet. A day later, he was downgraded to suicide precautions, which still sharply limited his access to a phone and ability to leave his cell, his lawyers said. 

On Friday, Allen's lawyers said he was reassessed and deemed not to be a risk, but was still held in a form of protective custody that resulted in him being held separately.