Houston police said Thursday morning that an officer accused of “penetrating” the U.S. Capitol building during last week's riot has announced his resignation from the department.

Houston Police Chief Art Acevedo said during remarks Wednesday that the Houston police officer -- on his own time -- attended the Trump rally in Washington and then “penetrated” the U.S. Capitol building last week.

There is an investigation underway and Acevedo said he is “highly confident” he will be facing federal charges. He is now on administrative leave, Acevedo told KPRC.

“There is no excuse for criminal activity, especially from a police officer,” Acevedo said. “I can’t tell you the anger I feel at the thought of a police officer and other police officers thinking they get to go storm the Capitol.”