SEATTLE (AP) — A sixth Seattle police officer is now under investigation after reporting their presence in Washington, D.C., during the violent U.S. Capitol insurrection, according to the Seattle Police Department.

The officer self-reported being there, the police department said on its blog Friday. Police did not say when the officer made the report.

The Office of Police Accountability, the city’s independent police watchdog, began investigating two Seattle officers after photos on social media showed them in D.C. on Jan. 6. Officers were told at that time to report to their supervisors if they had also been there.

The watchdog group is investigating to determine whether the officers engaged in any illegal activities or violated any department policies that day when thousands of pro-Trump supporters stormed the U.S. Capitol as Congress was meeting to certify Joe Biden’s presidential win.

The first two officers under investigation were placed on administrative leave.

Because the other four officers self-reported and have not yet been found to have violated any policy or law, they remain on duty, police said Friday. None of the officers’ identities have been released to the public.

Police Chief Adrian Diaz has said if any Seattle officers were directly involved in the insurrection at the U.S. Capitol, he will immediately terminate them.

The head of Seattle’s police officers union, Mike Solan, is also under investigation over his tweets that blamed, in part, the “far left” and Black Lives Matter activists for the violence at the U.S. Capitol.

Mayor Jenny Durkan and most Seattle City council members have called for him to apologize or resign over the comments. Solan has said he will not step down, and that he interpreted the calls to resign as “political rhetoric.”