DENVER (CBS4) – A teacher at Manual High School was placed on leave after officials say he brought a marijuana joint to school.

Manual High School (credit: CBS)

READ MORE: Booking Booster Shots Proves Challenging For Some Coloradans

The teacher says it was for an anti-pot campaign, but district officials say the project wasn’t approved by the school’s administration.

READ MORE: Denver Police Prepare To Protect The More Than 100,000 People Expected Downtown For Parade Of Lights

Three other staff members were also placed on leave for their involvement in the campaign.

MORE NEWS: 'There Was No Effort': Denver Police Officer Fired For Failing To Render Aid To Shooting Victim

Denver police are investigating possible criminal charges.