An Indiana middle school teacher was arrested after two students found her methamphetamine stash inside a hidden compartment on her hair scrunchie – and the 35-year-old woman came prepared for subsequent drug tests with a pouch of clean urine in her pants, police said.

Helfrich Park STEM Academy hosted a family fun night for students on Sept. 12, according to a probable cause affidavit obtained by Fox News Digital, and Sarah Duncan attended the event along with her daughter, who was a student at the school.

At the end of the event, around 6 p.m., Duncan posed with students in a photo booth, per the affidavit.

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Sarah Jayne Duncan

Sarah Duncan was booked into the Vanderburgh County Jail on Sept. 20 for criminal possession of methamphetamine and criminal possession of drug paraphernalia, police said. (Vanderburgh County Sheriff's Office)

"Both juveniles stated that Duncan let her hair down for the photo," Evansville Police Department officers wrote. "After the photo, the juveniles cleaned up the area and located a blueish colored velvet-type scrunchie with a white zipper on the table. They noticed the scrunchie was heavier than a typical scrunchie, they opened the zipper pouch and observed a glass vial that contained a white powder substance that the two believed to be drugs along with a cut straw with white powder."

They immediately notified another teacher, who instructed the students to throw the substance in the trash. That teacher, who could not be reached by Fox News Digital at press time, secured the scrunchie in her classroom and notified the school's principal and assistant principal.

Meanwhile, two janitors working the night of the event told police that Duncan was "frantically searching for some sort of hair tie" after the event had ended. Security camera footage from the school obtained by police showed Duncan wearing the scrunchie earlier in the evening.

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Helfrich Park STEM Academy

Two students at Helfrich Park STEM Academy in Evansville, Indiana, discovered that a pocket in Sarah Duncan's scrunchie contained a "glass vial that contained a white powder substance" on Sept. 12, police wrote. (Google Maps / Google Street View)

A field test for methamphetamine on the scrunchie, administered by responding police, allegedly came back positive.

Two days later, the school's deputy chief of staff and Evansville Police Chief Tim Alford accompanied Duncan to a nearby clinic for a drug urine screening, per the document.

The teacher's first two urine samples were too small and did not "reach the temperature for testing," and Duncan allegedly acted baffled, telling officers that she "[did] not know why her urine would not reach the appropriate level or temperature for testing."

While making a third attempt, police wrote, officers "observed an unauthorized collection container fall from Duncan's shorts."

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Vanderburgh County Jail in Indiana2

Since she was booked on Sept. 20 in the Vanderburgh County Jail, Sarah Duncan has been released on $1,000 bond and first appeared in court on Tuesday, Sept. 26. (Vanderburgh County Sheriff's Office / Facebook)

"Duncan stated that she was not aware of the pouch/container in her shorts until after she was providing her second sample," police wrote in their affidavit. "Duncan stated that she does not know how or when the pouch/container got into her shorts that day. Duncan stated that there may be another one of them at her residence but that they were not purchased by her, but by someone she knows who probably uses them to pass drug screens."

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Duncan was booked into the Vanderburgh County Jail last Wednesday on one count of criminal possession and one count of possession of drug paraphernalia and has since been released on $1,000 bond on the condition that she attend a drug rehab program, a court clerk at Vanderburgh Superior Court told Fox News Digital. Her first court hearing was scheduled for Tuesday.

Fox News Digital could not reach the school district for comment at press time. She was fired the day of her arrest, according to local outlet WFIE.

Duncan could not be reached for comment and has not yet been assigned a public defender. Her next court appearance is scheduled for Oct. 9.