One person was arrested after Garneau High School in Orléans received a threat by email.
Ottawa Police said they got a call around 6 a.m. Monday about the email, which included a mention of a gun.
Constable Chuck Benoit explained that the threat did not target one specific person or group but instead the school and staff as a whole.
A 19-year-old man was arrested but police have not laid charges.
Classes were cancelled on Monday as a result of the threat.
