An Idaho teacher is under investigation for WHY she fell asleep at her desk in a high school classroom last Thursday.

Authorities in Arimo, Idaho, an Eastern Idaho community, report the teacher, 32-year-old Chelsea Nicholes, was subbing at Marsh Valley High when students noticed she appeared to fall asleep after acting strange in class.

A resource officer was called to the classroom, and Nicholes was escorted from the school. Bannock County Sheriff's officials say her behavior was very much like someone who was under the influence of drugs, and toxicology tests are scheduled.  While her name was not listed on the county jail register, she is facing a charge of public drug intoxication.

She's also facing a disorderly charge, but officials didn't say if that's related to the classroom incident.