President Biden made an unexpected visit to the U.S. Capitol building to honor Capitol Police Officer Brian Sicknick, who is lying in honor in the rotunda.

Biden’s motorcade left the White House on Tuesday night at about 9:45 p.m. and arrived at the complex shortly after. Sicknick is only the fifth civilian in U.S. history to lie in honor at the Capitol, and the ceremony honoring him marks nearly a month since he suffered fatal injuries when a mob overran security and stormed the building.

Prior to Biden’s arrival, Sicknick’s flag-draped casket was brought to the rotunda at about 9:30 p.m. His fellow officers circled the tribute and paid respects to their fallen colleague.

Biden and first lady Jill Biden appeared shortly later and walked toward the memorial. Biden gave the sign of the cross, and then he and Jill Biden walked to Sicknick’s casket, where they both placed their hands over their hearts. Biden could be seen shaking his head as he paid tribute to the officer.

The couple departed the rotunda shortly after without addressing media.

“This evening, the President and the First Lady paid their respects to Capitol Police Officer Brian D. Sicknick as he lies in honor at the Capitol Rotunda,” the White House said in a statement.