HAILEYVILLE, Okla. – An Oklahoma agriculture teacher faces drug charges after he purchased methamphetamine from a student on multiple occasions, police said.

Officials at Haileyville High School recently re-instituted the school’s drug testing policy, and the change allegedly compelled one student drug dealer to roll over on a repeat customer – agriculture teacher Nathan Cato, Fox 23 reports.

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“We passed out the (drug testing) paperwork Thursday morning,” Jan. 7, principal Roger Hemphill told the news site.

Many students “were drinking water,” he said. “They were trying to flush their system. It was kind of comical.”

But it wasn’t long before one student “came into (Hemphill’s) office and informed him that he/she needed to talk with him,” District 18 Drug Task Force officer Kevin Fox wrote in a court affidavit cited by the McAlester News-Capital.

“During their conversation, the student informed Mr. Hemphill that he/she had sold to Mr. Cato an 8-ball of methamphetamine,” Fox wrote.

The principal immediately called Haileyvile Police Chief David Johnson, who relayed the case to the drug task force. Task force investigators interviewed the 41-year-old teacher, who initially denied the allegations, then changed his story, and later confessed to buying the drugs, according to investigators.

“Mr. Cato … stated that he asked to purchase methamphetamine from a student, but the purchase was not successful,” Fox continued. “Mr. Cato was informed that if there was methamphetamine inside his classroom we would locate it. Mr. Cato was informed he needed to tell us if there were any drugs inside his classroom, so that no students could possibly come in contact with it or take them.”

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With some prodding, Cato told police the meth was “in the trailer in the ag building” on school grounds, and led officers to the stash, the News-Capital reports.

Task force director Tim Turner told the Tulsa World officers recovered a “personal use” amount of meth.

Hemphill said he was truly shocked by the student’s accusations.

“You could have knocked me out of the chair with a feather, I was just so flabbergasted,” he told Fox 23, adding that Cato has taught at the school for 9 years without issue.

Police believe Cato made multiple drug transactions with the student, according to News on 6. The unidentified juvenile student is also facing criminal charges.

Cato was booked into Pittsburg County Jail the same day as the student’s report and was released two hours later. He was charged the next day with possession of a controlled substance in the presence of a minor and misdemeanor unlawful possession of drug paraphernalia, the News-Capital reports.

The former carries a potential sentence of up to 20 years in prison, if convicted.

Turner commended school officials for how they handled the situation.

“Haileyville has been nothing but cooperative,” he told the Tulsa World. “They contacted law enforcement right out of the box.”