A portion of a school in Woodland Park, Colorado was evacuated on Thursday morning due to security fears.
Woodland Park School District RE-2 says that a ticking sound was heard coming from a student's backpack at about 8am.
The decision was made to evacuate students in the wing of the school where the backpack was found to another part of the building.
Police opened up the backpack and found a metronome inside. The school district says that by 8:25am all students were back in class.