By KARMA ALLEN, ABC News

(CLARKSBURG, Va.) — A former Veterans Affairs nursing assistant has pleaded guilty in federal court to killing seven hospital patients by injecting them with unnecessary insulin, and assaulting another patient with intent to murder.

Army veteran Reta Mays, 46, pleaded guilty to seven counts of second-degree murder and one count of assault with intent to murder on Tuesday, following a two-year investigation into the suspicious deaths of seven elderly patients at a veterans hospital in West Virginia.

Mays, who worked at the Louis A. Johnson Veterans Affairs Medical Center in Clarksburg, faces up to life in prison for each count of second-degree murder.

Mays is accused of killing veterans Robert Edge Sr., Robert Kozul, Archie Edgell, George Shaw, Felix McDermott, Raymond Golden and a patient identified only as W.A.H., and of administering unnecessary insulin to another patient who was not diabetic, with the intent to kill him.

The patients all died of low blood sugar and severe hypoglycemia after being injected with unneeded insulin between July 2017 and June 2018. The victims, all male, were between the ages of 82 and 96.

Up until Tuesday, authorities had not identified Mays publicly. They previously described the person of interest as a former nursing assistant who had overnight access to the rooms of the veterans who died.

The U.S. attorney prosecuting the case called her acts “evil” and an FBI agent involved in the case said the veterans were betrayed.

“These eight veterans deserved respect and honor. They served our country and we all owe them a debt of gratitude,” FBI Acting Special Agent in Charge Michael Christman told reporters Tuesday. “They didn’t deserve to die at the hands of a nursing assistant who intentionally inflicted pain on them and their families.”

Mays was formerly employed by the West Virginia Regional Jail and Correctional Facility Authority. She was hired in 2005 and assigned to the North Central Regional Jail, where she was a correction officer until leaving in the fall of 2012, according to local media reports.

Officials said Mays’ motive in the case is still unclear, but that she could possibly reveal more details at her sentencing.

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