SALT LAKE CITY (ABC4) – A former Salt Lake City nurse was sentenced in federal court on Wednesday for fraudulently obtaining and tampering with opioid painkillers.

Nathan Pehrson, 41, of Sandy was sentenced to 36 months in federal prison after being convicted of three counts related to obtaining and tampering with the pain-killing narcotic hydromorphone.

A federal jury found that when Pehrson was working as a nurse in a surgical and trauma ward, he diverted hydromorphone from pre-loaded syringes for his personal use, and then replaced the pain medication with saline solution before they were placed back into circulation for medical use by other hospital staff on other patients, court documents say.

Hydromorphone is a powerful schedule II opioid drug that is used to treat patients with moderate to severe pain.

Pehrson was also convicted of making false statements to a special agent from the Food and Drug Administration about his illegal activity while under investigation for his crimes, according to the U.S. Department of Justice.

“We hope that this sentence of three years in federal prison deters every healthcare professional from using or diverting prescription narcotics,” said Acting United States Attorney Andrea T. Martinez. “We commend the work of the hospital staff who discovered and reported the illegal activity along with the work of our partners at the FDA for investigating this matter.”

Upon his release, Pehrson was also sentenced to an additional term of 36 months of federal supervised release.