By WCCO-TV Staff

MINNEAPOLIS (WCCO) — Police are investigating after a Northfield Public Schools employee was fired for allegedly putting a melatonin pill into the bottle of at least one infant at a child care center without family approval.

District officials say staff members at Early Ventures Childcare at the Northfield Community Education Center alerted them Monday that suspicious tablets were discovered in an infant care room.

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Police were informed of the situation, and two days later the employee told investigators they had put a child-sized pill into one bottle — although it’s possible more children were given the tainted bottles. Investigators believe the pills contained melatonin, a hormone that can induce sleep. The employee was fired that same day, and all parents and guardians were notified of the situation.

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Northfield Public Schools Superintendent Matt Hillmann described the suspect as a “rogue former employee,” and says his district is fully cooperating with the police investigation.

“I am confident this is an isolated incident,” Hillmann said.

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The Minnesota Department of Human Services is assisting in the investigation.