Portage Collegiate Institute was placed into lockdown on Wednesday after Portage la Prairie RCMP received threats against the school from an anonymous caller.
Police say an officer was at the school on an unrelated matter Wednesday morning when the call came in. The school was placed into lockdown as a precaution as more police resources were deployed to the scene.
An explosives detection dog and other police units responded at around 11 a.m. to search the area. No suspicious persons or items were located and the lockdown was later lifted.
Two people were detained and questioned during the investigation but were cleared of being involved.
The RCMP is continuing to work to identify the caller. Anyone with information is asked to contact Portage la Prairie RCMP at (204) 857-4445 or Crime Stoppers anonymously at 1-800-222-8477.