Reta Mays was not authorized to administer the drug
Reta Mays
Reta Mays
| Credit: West Virginia Regional Jail and Correctional Facility Authority/AP/Shutterstock

A former nursing assistant at a West Virginia veterans hospital pleaded guilty to federal murder charges on Tuesday for injecting seven elderly patients with unprescribed insulin in 2017 and 2018.

Reta Mays, who worked at the Louis A. Johnson VA Medical Center in Clarksburg, was charged with seven counts of second-degree murder and one count of assault with the intent to commit murder of an eighth person. According to prosecutors, she faces life in federal prison for each murder.

At a plea hearing on Tuesday, Mays admitted to purposely killing the seven victims, who were all staying in the hospital's surgical unit, known as Ward 3A.

TIME reports that Mays' voice cracked and she appeared to weep as she told the court that she had injected the victims with unprescribed insulin. The murders occurred when Mays worked overnight shifts at the hospital.

In charging documents released on Tuesday, prosecutors allege that Mays, 46, knowingly injected lethal doses of insulin into the veterans, causing their blood sugar levels to plummet to dangerously low levels. Seven of the victims died, while an eighth one recovered.

Mays was not authorized to administer the drug.

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According to the Washington Post, Mays served in the Army National Guard from November 2000 to April 2001 and again from February 2003 to May 2004. During her enlistment, she was deployed to both Iraq and Kuwait. She later had three sons.

During Tuesday's hearing, Mays told the judge that she was taking medication for post-traumatic stress disorder. Neither the prosecution nor the defense offered any explanation or motive for why Mays killed her victims.

Mays will be sentenced at a later date, and her attorney didn't immediately return PEOPLE's message for comment.

After the court hearing, Bill Powell, U.S. attorney in West Virginia, held a press conference in which he addressed the families of Mays' victims.

"Nothing we have done will bring your loved ones back," Powell said, according to USA Today. "But we do hope that the work of these agents and prosecutors honored the memory of your loved ones in a way that they so justly deserved and, in some small fashion, assuage the anguish you have suffered."