A former intensive care unit nurse in Oregon has been arrested for allegedly diverting fentanyl from medical drips and replacing it with tap water. 

The Medford Police Department said in a news release that Dani Marie Schofield was arrested on Thursday after a “lengthy investigation” into allegations of drug diversion at Asante Rogue Regional Hospital between 2022 and 2023. 

The seven-month investigation began in early December 2023, the department said, after hospital officials became “concerned with a rising number of central line infection cases” in patients at the facility. An internal investigation found that all of the cases involved patients in the intensive care unit. Schofield, who left the hospital in July 2023, had access to each of the patients, the police department said. 

“There was concern that Schofield had been diverting patients’ liquid fentanyl for her personal use and then replacing it with tap water, causing serious infections,” the police department said. 

CBS News previously reported that Schofield had agreed to a voluntary suspension of her nursing license in November, pending the results of an investigation. 

Police said that after an investigation that included interviews with nearly 100 people, a grand jury was convened to review the case. The grand jury indicted Schofield on 44 counts of second-degree assault. 

“A person commits Assault in the 2nd Degree if the person intentionally or knowingly causes serious physical injury to another,” the police department said. “The 44 charges reflect the total amount of patients that this investigation revealed to have been affected by Schofield’s criminal actions.”

Schofield was also named in a wrongful death lawsuit filed in February that alleged she stole fentanyl from a 65-year-old patient’s medical drip while he was in the hospital, leading to his death. 

The police department noted that medical experts consulted on the case said that the questionable deaths associated with Schofield’s case could not be directly attributed to the central line infections. 

Fentanyl is a powerful synthetic opioid is used in medical settings as a pain reliever. It’s also fueled the country’s overdose crisis, and its theft from hospitals is a longstanding problem.