A letter informed parents this week the teacher found feces on a classroom floor at Webster Elementary School in Belleville March 30, the Belleville News-Democrat reported Wednesday.
The teacher had the children go into a bathroom stall separately, remove their underpants, put their clothes back on and then display their underwear.
"The teacher was not present in the bathroom stall and at no time was your child exposed to the teacher," the letter stated.
The teacher was trying to determine which child was responsible and should be sent to the nurse.
Superintendent Dennis Craft confirmed the incident and said the school board voted Monday not to renew the teacher's contract.
"The teacher is no longer in the classroom and will not be in any classroom for the remainder of the year, and he will not return next year," he said.
The teacher was not identified and has been charged with no crime.
The children in the classroom were all special education students in third or fourth grade.