Brother Karl Walczak had been on leave since August, The Seattle Times reported.
Zachary Lell, chairman of the board at O'Dea High School, said the board learned of the allegations this week. He said Walczak allegedly molested a student while teaching at another Catholic high school in another diocese.
In a statement, the school said James Walker became acting principal when Walczak was called to New York to New York by the Christian Brothers to "assist in resolving a proof of claim in the Christian Brothers Institute bankruptcy proceeding."
Notable deaths of 2014 [PHOTOS]