Officer Brian D. Sicknick was injured while physically engaging with protesters Wednesday and returned to his division office, where he collapsed, Capitol Police spokeswoman Eva Malecki said in a statement. He was taken to a 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.