The school was secured by officers Tuesday. Students have since been dismissed in stages, under police supervision.

The Ottawa Police Service and Ottawa Catholic School Board are trying to get to the bottom of a threat situation at St. Patrick's High School.

The board says a threatening email was sent to the school on Tuesday morning. Police put three Alta Vista-area schools in 'shelter in place mode,' but later lifted it at all schools except St. Patrick's.

The Catholic school board released an update around 2:40 p.m., saying student dismissal would be done in stages, while the Ottawa Police Service supervised.

Any students remaining in the school were in classrooms with staff members. Students were allowed supervised washroom breaks, as needed.

As of 5 p.m., Tuesday, all students were out of the facility.

All after-school activities and games at St. Patrick's have been cancelled.

The board is expected to release information regarding tomorrow's school day at St. Patrick's, Tuesday evening.

Anyone with questions or concerns are asked to contact the school superintendent's office at 613-224-4455 ext. 2345 or communications at 613-294-3946 or 613-224-4455 ext. 3326.