A U.S. Capitol police officer has died a day after clashing with a pro-Trump mob at the Capitol.
United States Capitol Police Officer Brian D. Sicknick was injured while engaging with protesters Wednesday and returned to his division office, where he collapsed, Capitol Police spokeswoman Eva Malecki said. He was taken to a local hospital where he died about 9:30 p.m. Thursday.
Sicknick, who joined the Capitol Police in 2008, is the fifth person to die from Wednesday's violent clash in Washington. His death will be investigated by the Metropolitan Police Department in Washington, the statement said, as well as the Capitol Police and federal agencies.
Sicknick most recently served in the Capitol Police department's first responder's unit, the statement said.
Capitol Police fatally shot an Air Force veteran and ardent Trump supporter who was part of the mob that made it into the building. Three other people died in "medical emergencies" after the riot, officials said. Capitol Police officials, however, have not released many details about the circumstances of these other deaths.
News of the officer's death comes shortly after Capitol Police Chief Steven Sund resigned amid criticism of the department's response to rioters who broke through barricades, vandalized the building and clashed with police.
Sund's resignation will go into effect Jan. 16, just a few days before President-elect Joe Biden's inauguration, a police spokeswoman said Thursday. The head of the department's union also called for a "change at the top.
Lawmakers offered their condolences to Sicknick's family, including from House Minority Whip Steve Scalise, R-La., who has credited Capitol Police officers with saving his life during the congressional baseball shooting in 2017.
"Devastating news. Please join me in praying for our fallen Capitol Police officer’s family during this heartbreaking time," Scalise tweeted Friday.
House Appropriations Committee Chairwoman Rosa DeLauro, D-Conn., and Rep. Tim Ryan, D-Ohio, who oversees the subcommittee that funds the legislative branch, said that they will honor Sicknick's memory by holding those who instigated the mob "fully accountable."
Sen. Ben Sasse, R-Neb., said in a statement, "This is gut-wrenching news. None of this should have happened. Melissa and I are praying for Officer Sicknick's family and for the families of the four others who died. Our country aches for the families who mourn. Lord, have mercy."
This story first appeared on NBCNews.com.