Winnipeg police are investigating a threat against Sturgeon Heights Collegiate.

A letter went home with students last night.

It let parents know graffiti was found in a school bathroom, with a potentially threatening message.

Wednesday morning, police were on scene at the school.

Officers will be in the area all day.  

They're interviewing students and staff, to find out who is responsible for the threat.

Sturgeon Heights set out the safety protocols.

Students were asked not to bring big backpacks and purses to school, and only to enter through the west doors.

The letter sent home reads: “One of the school bathrooms was vandalized with graffiti and that message could be interpreted as a potential threat to the safety of our school on May 11, 2016.”

On Tuesday, Chief Superintendent Brett Lough said administration called all of the students down to the gym to talk about the situation prior to sending a memo and indicating the type of threat.

“Any time there is a date of an event in a school, where there is a threat of any shape, we will take that very seriously.”

Lough said, once the threat was identified, the administration sealed off the area. Part of in the investigation at this point is going through footage captured on hallway video cameras, which the division has been using for “many years,” he said.

Lough said at this stage, it’s believed the person responsible for the threat is a student, but police are working to finalize the right person.

The wording and specific nature of the threat is not being shared. It’s not clear if the threat has been removed from the bathroom. Lough said it may be used as evidence.

In addition to Winnipeg police officers being on scene Wednesday, Lough said school resources were also present.

“To support the school administration and safety is the priority,” he said.

He said some students are still at school and the school remains open. Some students did not attend school Wednesday, but it’s not clear how many stayed home.

- With files from Beth Macdonell