Six Capitol police officers have been suspended with pay and another 29 are under investigation following last month's deadly riot, the department said.
Capitol police spokesman John Stolnis told NBC News that the agency's Office of Professional Responsibility is looking into the actions of the 35 officers during the Jan. 6 attack.
The riot left five people dead, including Capitol police Officer Brian Sicknick.
"Acting Chief Yogananda Pittman has directed that any member of her department whose behavior is not in keeping with the Department’s Rules of Conduct will face appropriate discipline," Stolnis said.
NBC News reported in January that "several" U.S. Capitol police officers were suspended and at least 10 more were under investigation following the riot.
Pittman said at the time that video and other evidence discovered during an internal probe appears to show that some officers and officials violated department policies.
Rep. Tim Ryan, D-Ohio, who chairs one of the committees that oversees the Capitol police, told reporters that one of the suspended officers appeared to have taken a selfie with members of the mob.
Another officer was suspended after he was seen wearing a "Make American Great Again" hat and directing people inside the building, Ryan said.
Ryan said 10 to 15 more officers were being investigated, although he could not provide details about the extent of those investigations.
Capitol police Chief Steven Sund announced his resignation the day after the riot, amid intense scrutiny over the department's response to the siege.