A California man accused of attempting to assassinate President Donald Trump during the White House Correspondents' Association dinner has been indicted on an additional federal charge for allegedly assaulting a Secret Service officer with a deadly weapon.

Cole Tomas Allen, 31, of Torrance, California, was initially charged with attempting to assassinate the president and two firearms counts following the April 25 incident at the Washington Hilton. A federal grand jury in Washington, D.C., has now added a charge of assaulting a federal officer with a deadly weapon to his indictment.

Authorities say Allen was armed with guns and knives when he ran through a security checkpoint during the annual dinner event. A Secret Service officer was shot once in a bullet-resistant vest during the confrontation. The officer fired five shots without hitting anyone, according to officials. The attack disrupted and ultimately ended the high-profile event early.

The addition of the assault charge indicates that investigators believe Allen fired the shot that struck the officer's protective vest. Acting Attorney General Todd Blanche had indicated last week that authorities wanted to review additional ballistics evidence before making that determination.

Allen was injured during the incident but was not shot. He was initially placed on suicide watch following his arrest but was removed from that status over the weekend. His attorneys have complained about his jail conditions, citing confinement in a padded room with constant lighting, repeated strip searches, and placement in restraints outside his cell.

Allen's defense team has challenged the government's case, questioning both the evidence for intent to kill the president and claims that their client fired the shot that struck the officer. If convicted on the attempted assassination charge alone, Allen faces a maximum sentence of life in prison.