(CBS) — Authorities have identified the suspect killed by police after ramming his vehicle into officers at a barricade outside the U.S. Capitol as Noah Green, a 25-year-old man from Indiana.

One U.S. Capitol police officer was killed and another officer was injured in the attack. The slain officer has been identified as William “Billy” Evans, an 18-year veteran of the Capitol Police.

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“It is with a very, very heavy heart that I announce one of our officers has succumbed to his injuries,” Capitol Police Acting Chief Yogananda Pittman said at a news conference Friday.

Two law enforcement sources involved in the investigation confirmed to CBS News that the suspect Friday’s assault at the Capitol is Noah R. Green, 25, of Indiana.

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Green did not appear to be known by law enforcement. He was an African American man who also had recent ties to Virginia He was not on any watch lists and appeared to be a single actor, according to a federal law enforcement official and a Capitol Hill source.

A U.S. official involved in the investigation said that “everything is coming back negative” on Green across all law enforcement databases.

Before it was taken down, Green’s profile on Facebook made it clear he was a follower of Nation of Islam leader Louis Farrakhan.

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Noah Green, of Indiana, has been identified as the man who drove his car into a barricade at the U.S. Capitol, killing one police officer and injuring another, on April 2, 2021. (Source: Facebook)

Green rammed his car into the officers at 1:02 p.m., then exited his car and lunged at them. The officers then “fired upon the suspect,” Pittman said. According to multiple sources, one of the officers was stabbed in the face. It’s not clear whether this was the officer who did not survive.

The officers were struck near a security checkpoint on Constitution Avenue.

Pittman said after the driver rammed the officers at the barricade, he got out of the vehicle and was shot by Capitol Police officers after he ran “aggressively” at officers with a knife.

CBS News reports the at least one officer was airlifted to an area hospital for treatment.

Soon after 1 p.m., Capitol Police sent an initial alert to congressional staffers, warning them of an “external security threat.” Within about an hour and a half, police sent another alert saying that the threat had been “neutralized.”

The Capitol lockdown has been lifted, but a large police presence remains in the area as an investigation is underway into what led to the incident and the FBI is on scene. There does not appear to be any ongoing threat.

Video posted online showed a dark blue-colored sedan crashed against a vehicle barrier and a police K9 inspecting the vehicle. Law enforcement and paramedics could be seen caring for at least one unidentified individual.

House Speaker Nancy Pelosi has ordered the flags at the Capitol to be flown at half-staff because of “the death of a U.S. Capitol Police Officer in the of duty today,” her spokesman tweeted Friday afternoon.

The incident comes nearly three months after rioters overran the building in a deadly attack on January 6. The resulted in the deaths of five people, including Capitol Police Officer Brian Sicknick. Two Capitol Police officers also died by suicide after the attack, and dozens of officers were injured.

After the January 6 rioting at the Capitol, fencing was erected around the Capitol complex, and thousands of National Guard troops were sent to Washington. That security fencing was taken down last week, although a layer of inner fencing around the Capitol building itself remains in place.

The barricade where the incident occurred is a checkpoint on the Senate side of the Capitol and was in place before temporary security fencing was erected. There were fewer people at the Capitol Friday since Congress is in recess; most lawmakers are in their home states. However, other congressional staff, as well as reporters and police, were in their offices.

CBS Baltimore, Andres Triay, Michael Kaplan, Kris Van Cleave and Rebecca Kaplan contributed reporting.

CBS 2 Chicago Staff