Under the cover of night, prosecutors say, the registered nurse slipped into her patients' rooms and secretly administered them fatal doses of insulin.

Prosecutors say Heather Pressdee's actions led to the deaths of multiple people in her care and went undetected for nearly three years until police in Western Pennsylvania arrested her after two men died from overdoses in December. Another man in the same care facility overdosed but survived.

Investigators now believe Pressdee's insulin injections were linked to the deaths of at least 17 additional patients, according to a press release issued Thursday from Pennsylvania Attorney General Michelle Henry.

The Pittsburgh-area nurse faces two new counts of first-degree murder, 17 counts of attempted murder, and 19 counts of neglect of a care-dependent person in connection to the crimes committed at five Western Pennsylvania care facilities dating as far back as 2020.

She was arraigned Thursday by Butler County Court of Common Pleas Judge Maura Palumbi and waived her preliminary hearing on her charges, Henry said.

Pressdee's attorneys, Jim DePasquale and Phil Di Lucente, released the following statement to USA TODAY Friday:

"This a very complex and serious matter... Counsel for Ms. Pressdee is cooperating with the prosecution team and investigators. The goal from the very beginning of these matters was to not have the death penalty imposed. We are in pursuit of that goal."

In all, Pressdee stands accused of administering excessive amounts of insulin to 22 patients − some who were diabetic and required insulin, and others who did not need the drug at all.

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The initial patient deaths

Pressbee was disciplined or fired from a dozen places of employment over her career before she started working at Quality Life Services, a nursing facility in Butler County, Pennsylvania, according to court records.

The slain victims she was initially charged with killing −a 55-year-old man and an 83-year-old man − died on Dec. 4 and on Dec 25, prosecutors said.

The victim who survived after emergency hospitalization, a 73-year-old man, was administered a potentially-lethal dose of insulin on Aug. 31, 2022.

So far prosecutors say at least 17 patients died in her care

In addition to Quality Life Services, the alleged crimes happened while Pressdee was employed at:

• Concordia at Rebecca Residence
• Belair Healthcare and Rehabilitation (Guardian)
• Premier Armstrong Rehabilitation and Nursing Center
• Sunnyview Rehabilitation and Nursing Center

Of the 22 mistreated patients who had been in her care, 17 died shortly after the dose was administered and another patient died a few months after the dose, Brett Hambright, a spokesperson for Henry's office told USA TODAY Friday.

Four victims, Hambright said, survived their insulin doses.

All the victims ranged from age 43 to 104.

Pressdee is charged with first-degree murder in the cases where "physical evidence is available to support the cause of death," Henry wrote in the release. Attempted murder is charged in cases where the victims survived or their cause of death was not determined by a medical examiner.

Pennsylvania Department of State records show Pressdee's license, issued in 2018, was suspended in July.

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Insulin administered under the cover of night

According to prosecutors, Pressdee often administered the insulin during overnight shifts "when staffing was low" and "emergencies would not prompt immediate hospitalization."

According to a criminal complaint, Pressdee "admitted to harming, with the intent to kill," all the patients named in the complaint. Her conduct, police wrote, spanned a five-year period at 11 facilities in four counties across the state: Butler, Armstrong, Allegheny and Westmoreland.

Text messages reportedly obtained from Pressdee's cell phone by investigators also revealed disturbing comments she made from April 2022 through January 2023.

In a Sept. 6, 2022 text to her mother, "complaining about a male resident yelling" she wrote, "I drugged him already and I don't know how he is awake."

"I can't with this lady tonight," she allegedly wrote in a Dec. 25 text to her mother. "She's going to get pillow therapy."

In one case involving one of Pressdee's patients, the woman was taken to an emergency room where a doctor found she had significantly low blood sugar, the complaint continues. During an interview with detectives, when asked why she administered insulin to the patient, Pressdee said the patient looked at her like an animal would, helpless and like she needed something. Police also said she told them the patient had "no quality of life."

“The allegations against Ms. Pressdee are disturbing. It is hard to comprehend how a nurse, trusted to care for her patients, could choose to deliberately and systematically harm them,” Henry said. “The damage done to the victims and their loved ones cannot be overstated. Every person in a medical or care facility should feel safe and cared for, and my office will work tirelessly to hold the defendant accountable for her crimes and protect care-dependent Pennsylvanians from future harm.”

Online records showed Pressdee remained jailed without bond Friday.

Anyone with information about the case is asked to call 888-538-8541.

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at [email protected] and follow her on X @nataliealund.