Hamilton police arrested three teenagers and a 36-year-old woman following a “series of incidents” that happened both on and off school property on Thursday. 

Just after 9:30 a.m., Hamilton police said they were called down to Sir Allan MacNab Secondary School to investigate an alleged assault.

Const. Krista-Lee Ernst told CTV News Toronto there was an “altercation” between two students.

As a result of the investigation, police arrested a 16-year-old boy and a 17-year-old girl for “assault level one.”

“Several other incidents occurred and a 16-year-old female has been arrested for Uttering threats and a 36-year-old female has been arrested for Cause Disturbance,” the news release reads.

Police say the 36-year-old did not work at the school but did not provide any additional information about her identity.

Just before noon, Sir Allan MacNab was placed under a Hold and Secure as a precaution, and at around 12:30 p.m., it was lifted.

The investigation is ongoing, and police ask anyone with information to contact them at 905-546-4925. Anonymous tips can also be provided with Crime Stoppers at 1-800-222-8477 or online at http://www.crimestoppershamilton.com.