WASHINGTON — A U.S. Capitol Police officer who died after a man rammed his car into him and another officer at a barricade was identified as an 18-year veteran of the force.

William "Billy" Evans joined the department in 2003 and was a member of its first responders unit.

President Joe Biden said in a statement that he and his wife were heartbroken to learn of Friday's attack and expressed condolences to Evans' family. He directed flags at the White House to be lowered to half-staff. House Speaker Nancy Pelosi hailed Evans as a "martyr for our democracy." She and Senate Majority Leader Chuck Schumer both spoke Friday with members of Evans' family.

The death is the latest moment of sorrow for a department after the loss of Brian Sicknick, who clashed with rioters during the Jan. 6 insurrection and died a day later, and Howard Liebengood, who committed suicide days after that.

Video shows the driver of the crashed car emerging with a knife in his hand and starting to run at the pair of officers, Capitol Police acting Chief Yogananda Pittman told reporters.

Authorities shot the suspect, identified by law enforcement officials as 25-year-old Noah Green. He died at a hospital.

Investigators were digging into his background and examining whether he had any history of mental health problems as they tried to discern a motive. They were working to obtain warrants to access his online accounts.

"Our thoughts and prayer are with the Officer who passed and his family," Larry Cosme, national president of the Federal Law Enforcement Officers Association, said in a statement. "He gave his life in dedication to protecting our nation's democracy and should be treated as a national hero. Our prayers also remain with the second officer battling injuries sustained in the attack. We hope for a swift recovery and commend both officers for their courageous actions."