Watertown, N.Y. – A fourth-grade teacher in a northern New York school district has been placed on administrative leave after being accused of having white students bid on black classmates during a mock slave auction. The mother of one of the black students told CBS affiliate WWNY-TV the incident happened Tuesday at North Elementary School in the Watertown City School District.

"He and another African American child were put up in the middle of the class and told they were now slaves," the mother, Nicole Dayes, told the station in an email. "The teacher then started the 'bidding' by assigning prices to the Caucasian students. After the winning bid was placed, my son was then told how slaves would take the slave owners last name and what he was to call the slave owner by. Then my son and the other 'slave' were instructed to call the Caucasian child by 'master' and the child's last name."

A statement from the school district said the teacher had been placed on leave during a district investigation launched after parents complained she had "exercised poor judgment in teaching a recent lesson."

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Parents were outraged and surprised by the incident, WWNY reported.

North Elementary School in Watertown, N.Y. WWNY-TV

"I was taken aback, shocked actually to think that a school would actually do something like that in today's day and age. If it actually happened, I think it's absolutely ridiculous," said David Ackley, father of a 4th grade student.

This is not the first time a teacher has held a mock slave auction in a classroom.

A fifth-grade teacher at a private school in Westchester County was fired in March after parents complained she held mock "slave auctions ." The Chapel School in Bronxville agreed to hire a diversity officer after the state attorney general's office investigated.

In 2017, a mock slave auction in a 5th grade class at a school in Maplewood, New Jersey sparked outrage.