"It is with profound sadness that I share the news of the passing of Officer William 'Billy' Evans this afternoon from injuries he sustained following an attack at the North Barricade by a lone assailant," Pittman said in a statement.
Evan began his service with the Capitol Police on March 7, 2003 and was a member of the Capitol Division's First Responder's Unit, Pittman said.
Earlier on Friday, a man ram his vehicle into two Capitol Police officers at an access point near the Capitol building. Pittman said during a press conference that the suspect exited his vehicle and tried to attack police officers with a knife before he was shot and killed.
Evans died from injuries he sustained in the attack.
Washington Metropolitan Police Chief Robert Contee said during the press conference that the attack does not appear to be terrorism-related, but the investigation is ongoing and investigators will continue to see if there are any links to terrorism.