A US Capitol police officer died Thursday evening from injuries sustained “during the physical confrontation” with pro-Trump rioters who descended on the US Capitol the day before the authorities.

The officer, Brian D. Sicknick, was only the fourth member of the force to be killed on duty since it was founded two centuries ago. After the chaos of Wednesday’s siege and the accusations that filled the waves in the air the next day, there was silence on the Capitol grounds late Thursday as hundreds of police officers from numerous agencies lined the streets to pay tribute to their fallen comrade.

But the loss of life also underscored the failure of law enforcement to prevent the siege of the Capitol. And with the leaders of both political parties calling for an investigation, it seemed likely to lead to calls for profound changes to the Capitol Police.

The circumstances surrounding Mr. Sicknick’s death were not immediately clear, and Capitol Police said only that he “died of on-duty injuries”. At some point in the chaos – when the mob raged through the halls of Congress while lawmakers were forced to hide under their desks – he was hit by a fire extinguisher, according to two police officers.

“He went back to his department office and collapsed,” the Capitol Police said in the statement. “He was taken to a local hospital where he succumbed to his injuries.”

Mr. Sicknick, who joined the force in 2008, died on Thursday around 9:30 p.m., Capitol Police said in a statement. The Washington Police Department Homicide is one of several law enforcement agencies involved in an investigation into his death and the general circumstances surrounding the violence in the Capitol.

The officer’s death brings Wednesday’s deaths from Mayhem to five. One participant in the pro-Trump rampage, Ashli ​​Babbitt, was fatally shot and killed by a Capitol police officer inside the building while climbing through a broken window into the speaker’s lobby. Three other people died after allegedly experiencing medical emergencies in the Capitol area, police said.

It was unclear where Mr. Sicknick’s encounter with the rioters took place, but photos and a video posted by a local reporter on the night of the mayhem showed a man spraying a fire extinguisher outside the Senate Chamber, leaving a small number of Police officers enter the area on a nearby staircase.

Legislators in both chambers and by both parties promised to find out how those responsible for the security of the Capitol had allowed a violent mob to enter the building. The House Democrats announced a “robust” investigation into the law enforcement collapse.

Three of the leading security officials in Congress – Steven A. Sund, Capitol Police Chief, Sergeant Paul D. Irving, and Sergeant Michael C. Stenger – announced their resignation Thursday.

The NCOs are responsible for the security in the chambers and the associated office buildings, while Mr. Sund supervised around 2,000 employees of the Capitol Police – a force that is larger than that of many small towns.

Earlier on Friday, Ohio Representative Tim Ryan, a Democrat who heads the Home Funds Subcommittee that oversees the Capitol Police’s budget, expressed grief over the death of Mr. Sicknick in a Twitter post.

“This tragic loss is a reminder of the bravery of the law enforcement officers who protect us every day,” wrote Ryan.

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Representative Rosa DeLauro, a Connecticut Democrat who chaired the House Appropriations Committee that opened a law enforcement review to the Capitol riot, said her “heart breaks at senseless death.”

“To honor his memory, we must ensure that the mob that attacked the People’s House and those who instigated them are brought to justice,” she said on Twitter.

Hundreds of police and rescue workers lined the streets by the Capitol for a moment of silence to honor Mr. Sicknick on Thursday evening. They stood in lines on Constitution Avenue and 3rd Street, saluting in silence as a police car drove through town for Mr. Sicknick, according to videos from local reporters.

Police said in their own statement that “the entire USCP division expresses its deepest condolences to the family and friends of Officer Sicknick for their loss and mourns the loss of a friend and colleague.”

Officials said around 50 police officers were injured when the mob flooded barricades, threw objects, smashed doors, broke windows and overpowered some of the police officers who tried to withstand the advancing crowd.

Capitol Police reported 14 arrests during the raid, including two people alleged to have assaulted a police officer. Local police arrested dozens of other people, mainly related to illegal entry and violations of the city’s curfew on Wednesday evening.

The Capitol Police are solely responsible for protecting the Capitol and the surrounding area.

Over the course of two centuries, the force has evolved and its mission has shifted and grown with the nature of the threats to the institution.

One event that had one of the most profound effects on the armed forces occurred on March 1, 1954, when Puerto Rican nationalists opened fire from the visitors’ gallery on lawmakers below and wounded five. Shortly afterwards, the police were issued weapons for the first time.

Exactly 17 years later, on March 1, 1971, an explosion broke through a toilet on the ground floor of the Senate wing. The Weather Underground, a militant left-wing group that carried out a series of bomb attacks in the late 1960s and 1970s, took responsibility. The incident resulted in all visitors having to be checked for weapons and explosives.

The first recorded death of a member of the armed forces was in 1984 when Sgt. Christopher Eney, 37, was killed during a training drill.

The last time a Capitol police officer was killed on duty was in the summer of 1998 when police officer Jacob J. Chestnut and Detective John Gibson of Russell Eugene Weston Jr., a man tormented by visions of an oppressive covenant, Government were fatally shot.

Mr. Weston, shot and injured in the incident, stormed into the heart of the nation for law and order. It all happened in a matter of minutes and reached its bloody conclusion when it reached the majority whip office complex on the first floor.

A fourth person, Angela Dickerson, 24, a tourist, was injured but recovered.

President Bill Clinton called the shooting at the eastern front entrance to the nation’s legislative forum “a moment of ferocity on the doorstep of American civilization”.

Legislators of both parties said at the time that they were hoping the bloodshed would allow a moment for reflection when partisan divisions could begin to heal.

Two decades later, the fourth Capitol Police officer in history was killed.

Emily Cochrane and Katie Benner contributed to the coverage.