SMITHVILLE, Mo. – A Smithville High School teacher believes he may have been drugged.

Police are investigating at the school after the teacher developed “unusual symptoms that required him to seek medical attention” last Tuesday. Neither police nor school officials named the teacher, but the school district confirmed this week that an investigation is underway to determine if someone may have spiked his coffee, WDAF reports.

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“During a school day last week, one of our employees consumed a beverage that may have been laced with an unknown substance,” Smithville Superintendent Todd Schuetz wrote in a letter to parents. “We understand that this matter is likely being talked about in community circles and it is drawing attention from local media. We wanted you to know that we are aware of the situation and acting accordingly.”

Schuetz did not provide any details about the incident, citing medical privacy laws, but confirmed “local law enforcement is aware of the situation” and directed anyone with information to contact the Smithville Police Department, KCTV reports.

Students told WADF their teacher discussed the issue with them in class.

“I do remember him talking about having a sudden heart problem last week and him going to see a doctor because he had a really high heart rate,” junior Austin Roberts said. “I think whoever did it, should pay the consequences. Drugging somebody regardless of what they did isn’t right.”

Classmate Brandon Butts, a senior, said he couldn’t image why anyone would want to harm the teacher.

“He’s an insanely nice guy,” Butts said, “I could never see anyone holding anything against him.”

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Smithville Police told WDAF they sent the teacher’s coffee to the state lab to be tested. The teacher has since returned to school, officials said.

The incident sparked a range of reactions online.

“My kids go to school in Smithville … if they are putting stuff in teachers’ drinks, what will the kids do to each other?” Kenna Tanner questioned on Facebook.

“This could happen at any school,” Nina Gomez posted. “I would not hold this against Smithville in any way.”

“I agree this stuff happens everywhere but what drives me crazy about this district is that they don’t notify parents in a timely manner. It’s not until the media gets ahold of whatever the story is that they send out a blast to parents,” Janet George wrote. “This has happened time and time again since we’ve had kids in school, which is going on seven years now.”

“These kids are out of control,” Andrew Elkins added.

“This makes me so sad,” Tracie Calhoun wrote. “Smithville is a wonderful district with an incredible staff.”