RCMP Cpl. Dave Tyreman did not identify the school in the Peace River South School District.
He says police, school officials and the Children's Ministry are investigating.
Sgt. Scott West of the RCMP detachment in Dawson Creek says he understands the matter has raised concerns in the community since it was reported to Mounties on Oct. 23.
West says parents should call police if they noticed their children acting in a strange or unusual manner or if they sought medical care.
The district operates 20 schools and oversees about 3,600 students in Dawson Creek, Chetwynd and Tumbler Ridge.