The news of another violent attack on the US Capitol grounds sent shockwaves through Washington, DC, Friday, shattering the sense of relative calm at the start of the holiday weekend just three months after the January 6 insurrection.

Capitol Police Officer William "Billy" Evans, an 18-year-veteran of the force, lost his life in the attack.

In the weeks since former President Donald Trump left office and President Joe Biden took command, the seat of government had begun to take on a tenor of something akin to a humming efficiency.

Covid-19 vaccinations are accelerating at an ever-increasing clip. The coronavirus economic rescue legislation sped through Congress, albeit with party-line approval.

A sense of business-as-usual had returned to the Capitol after four years in which the former President sowed constant turmoil and chaos, ultimately fomenting an uprising.

Friday's attack made it plain that the Capitol and its occupants remain a vulnerable target.

Memories of the political violence on January 6 were beginning to recede and Trump and his allies have attempted to whitewash the dangers of that day, with the former President going so far as to falsely suggest that the insurgents were "hugging and kissing" police officers and posed "zero threat."

Much is still unknown about the motivations of the suspect involved in the current attack.

Identified by federal and local law enforcement sources as Noah Green, who slammed his vehicle into the Capitol's north barricade shortly after 1 p.m. ET, striking two US Capitol Police Officers before exiting his car and running toward officers with a knife before he was shot by police.

One federal said he was 25 years old.

Posts on Green's social media accounts suggest he was struggling with mental illness, including paranoia and delusion -- as he wrote about suffering from "multiple home break ins, food poisonings, assaults, unauthorized operations in the hospital, mind control."

Green, an apparent admirer of Nation of Islam leader Minister Louis Farrakhan, posted a video with a caption stating that the "U.S. Government is the #1 enemy of Black people!" and attributed his "terrible afflictions" to forces he presumed were part of the "CIA and FBI, government agencies of the United States of America."

But it was painfully clear on Friday as Capitol Police Officer William "Billy" Evans, an 18-year-veteran of the force, lost his life in the attack, and another officer was injured, that members of Congress have not yet managed to find the balance between preserving the accessibility of the Capitol building and ensuring the safety of the men and women who protect it.

It has only been a matter of weeks since the temporary barbed wire fencing erected around the Capitol was taken down. But the January breach of the Capitol has created the perception that the building is still vulnerable to attack, and proposals to secure it are caught up in partisan infighting.

Authorities said during a news conference that they do not believe Friday's attack was related to terrorism.

And when asked whether the suspect appeared to be targeting any one member, authorities said Green, who had not been named at that point, was not known to Capitol Police.

But that may do little to comfort the many congressional aides and members who feared for their lives on January 6 and still feel unsafe going to work.

"I never thought when I was elected to Congress that coming to work would be a dangerous workplace.

In candor, it has become a dangerous place. When you go outside and you're coming back in, you're on guard, you're looking, you're wondering what's going on," California Rep. Ro Khanna, a Democrat who was at the Capitol Friday said

"I do think they're going to have to rethink probably the perimeter and security of the entire complex -- the Supreme Court, Library of Congress, Capitol, really think how they can keep it safe but allow Americans to still visit," the California Democrat added.

Biden, who had left the White House to spend Easter weekend at Camp David at the time of the incident, alluded to the painful few months that the Capitol Police force has endured in a statement.

The President said he and his wife Jill were heartbroken upon learning of the attack that killed Evans and "left a fellow officer fighting for his life." The second officer is now in stable condition.

"We know what a difficult time this has been for the Capitol, everyone who works there, and those who protect it," Biden said.

"I want to express the nation's gratitude to the Capitol Police, the National Guard Immediate Response Force, and others who quickly responded to this attack. As we mourn the loss of yet another courageous Capitol Police officer, I have ordered that the White House flags be lowered to half-mast."

Congress debates Capitol security recommendations

In the hyper-politicized environment surrounding the January 6 attacks and Trump's role in inciting his supporters to violence, the question of security at the Capitol has generated a heated debate in Congress in recent weeks.

Many members from both parties demanding a clearer justification for the temporary fencing topped with razor wire, while some stalwart Trump allies on the Hill have attempted to minimize the dangers that police faced in the January riot.

Though the suspect in Friday's incident was not able to breach the barricade, and National Guard troops came in immediately to serve as backup,

Evans' death raised fresh questions about the continuing risks to front-line Capitol Police officers.

After conducting a six-week review of security at the Capitol at the request of House Speaker Nancy Pelosi, Retired Lt. General Russel Honoré and other members of the task force he headed urged Congress to increase Capitol Police staffing.