SASKATOON -- A 16-year-old boy has been charged with uttering threats after a threat was allegedly made involving Holy Cross High School.

Around 11 p.m. Tuesday the Saskatoon Police Service became aware of a social media post showing a picture of the high school’s floorplan, Staff Sgt. Maj. Grant Obst said Wednesday afternoon.

"We do know that the diagram was posted to a particular media platform and then subsequently taken from that platform and shared on Snapchat so a lot of people found out about this very quickly last night and this morning."

The diagram and the accompanying text indicated the high school was going to be the subject of an attack, Obst said. The date on the diagram was Dec. 17.

Officers responded immediately, and the 16-year-old was in custody within three-and-a-half hours, Obst said. After he was charged the teen was released on conditions, one of which was not being allowed anywhere near the school. He is scheduled to appear in court next year.

"There is a working theory that this would be an extremely misguided, misjudged joke and that's part of what the investigators are looking at. We're confident that again, there's no public threat."

A search of the teen's home recovered nothing capable of carrying out the kind of attack outlined on the diagram, Obst said.

"I can't tell what was in that young man's mind at 11 p.m. last night but we have come to a point where we are certain that he didn't intend to go into the school and shoot up the place."

A Facebook user named Janelle Roy was one of those who shared the map, saying in a post that her kids would stay home from school because they felt "absolutely terrified."

"I'm feeling sick to my stomach, as I'm sure plenty of children and parents are," she said.

A message sent was sent by the school's administration to parents informing them about the alleged threat.

"It takes the whole community to ensure we provide a safe learning environment for students and staff. Students, families, teachers and staff each have the responsibility to contribute to the safe, positive school environment we all want for our children," the message said.

Police were present at the school Wednesday.

"We'll continue to work with the school to make sure everyone feels safe again and they are comfortable with their safety," Obst said.

"We're the police and that's what we do."

In a Facebook post earlier Wednesday, police said a large amount of misinformation is being shared online, including that there may have been gang involvement in the incident. Investigators have no evidence to suggest that is the case, the post said.

In the post, Saskatoon police asked that people be aware of what they share on social media and encourage people to check with a credible source.