SPRINGFIELD, Ill. (WAND) - A Springfield-area dentist accused of tampering with drugs administered to patients has been indicted by a federal grand jury. 

Prosecutors said Phillip Jensen, 61, of Rochester, who is authorized by the Drug Enforcement Administration to dispense controlled substances, adulterated fentanyl that was meant to be used as an anesthesia in patient surgeries. Before surgery, he allegedly pierced fentanyl vials, removed half of the drug and set it aside for personal use. After that time, prosecutors said he refilled vials with another solution and administered to patients the fentanyl that had been adulterated. 

The adulterated fentanyl was then at half its labeled strength, a press release from prosecutors said. 

Jensen is accused of doing this beginning as early as December 2019 and continuing to at least Aug. 17, 2020. 

Jensen faces eight counts of drug diversion, eight counts of acquiring a controlled substance by fraud, one count of tampering with consumer products and three counts of false statements related to health care matters. Related to the tampering charge, prosecutors said the adulterated fentanyl caused serious bodily injury to a patient it was administered to. 

A detention hearing for Jensen is scheduled for 11 a.m. on Feb. 9, 2022. If he is convicted, statutory penalties include as long as 20 years in prison for drug diversion, up to four years behind bars for acquiring a controlled substance by fraud, up to 20 years for tampering with consumer products, and up to five years in prison for a false statement related to health care matters. 

The government is represented in prosecution by Assistant U.S. Attorneys Douglas McMeyer an Sierra Senor-Moore. The case was investigated by the DEA with the help of the Sangamon County Sheriff's Office.Â