A physics teacher stopped a police search on Thursday after he realized the thing that they were looking for was in his closet.

GUN SCARE Do You Think Guns Should Be Allowed In School? Hear Mother's Frantic 911 Call

Police were called to the Plymouth-Canton Educational Park Thursday morning after a mother reported the teacher had carried a long gun into the high school in Canton Township.

About a dozen police cars were seen in front of the building as officers searched the school complex.

Students and teachers were put on code red alert and ordered to stay in their classrooms with the lights shut off, Local 4 reported.

The physics teacher stopped the search when he realized the BB gun locked in a closet in his classroom had caused the scare.

He reportedly took the gun to school to use it as part of a physics experiment, according to police.

The superintendant of the school district told Local 4 that the teacher had been given permission in the past to use the gun for experiments, but had not asked for permission to take it Thursday.

Officers had the driveway entrances to the school blocked and did not allow students or teachers into the complex. The lockdown reportedly caused delays on Beck Road in both directions for about an hour.

Police continued to search the school and allowed students in after they found it to be safe.

The teacher was not arrested, but police will present the case to the Wayne County prosecutor for further investigation.