HOUSTON — A Houston police officer suspected of taking part in the mob attack on the U.S. Capitol is under investigation, the police chief said Wednesday.

The officer has been placed on administrative leave and will face a disciplinary review hearing on Friday, said Houston Police Chief Art Acevedo. The patrol officer is an 18-year veteran with the department.

The officer attended a Jan. 6 rally in Washington, D.C., in support of President Donald Trump, which is allowed under the First Amendment, Acevedo said. But investigators determined the officer later joined the mob that breached the Capitol building.

Acevedo did not identify the officer, but in an interview with the Houston Chronicle, Tam Pham confirmed he was the officer and told the newspaper: “I shouldn’t have done it. I was there to take pictures.”

He declined to say if he entered the Capitol.

“A lot of stuff happened that day,” Pham said. “I wasn’t in the right mind.”

Authorities began investigating the officer after a Houston resident on Sunday emailed Acevedo a photo showing him at the rally draped in a Trump flag.

“But this individual has been determined to have actually penetrated the Capitol ... There is no excuse for criminal activity, especially from a police officer. I can’t tell you the anger I feel at the thought of a police officer and other police officers thinking they get to storm the Capitol,” Acevedo said.

Rioters violently clashed with authorities as they forced their way in the Capitol to try to stop Congress from certifying President-elect Joe Biden’s victory.

Five people died during the siege, including a Capitol police officer. More than 100 people have been arrested on charges stemming from the violence.

The police chief did not provide additional details about allegations against the Houston officer, citing an ongoing police and FBI investigation.

Acevedo said he believed there was a “high probability” the officer would face federal charges.

A spokesman for the Houston Police Officers’ Union did not immediately return a call seeking comment.

Officers from various law enforcement agencies around the country, including in Las Vegas and Maryland, are also being investigated for possibly taking part in the mob attack on the Capitol.