Genene Jones, the nurse serving 99 years in a Texas prison for killing a 15-month-old girl in 1982, has been indicted on a charge of first-degree murder in the 1981 death of a 2-year-old girl, authorities said Wednesday.

The Bexar County grand jury separately indicted Jones, 66, last month in a third suspicious death, that of an 11-month-old boy in 1981. The district attorney's office said at the time that Jones is now suspected of having killed as many as 60 infants in Bexar and Kerr counties.

Genene Jones in an undated prison photo. Texas Department of Criminal Justice / AP

Jones, who has been dubbed "the Angel of Death" and "the Killer Nurse," is scheduled to be released from a state prison in Gatesville next March under a law that was in effect at the time she was convicted. But District Attorney Nico LaHood said she would be held on $1 million bond and extradited to Bexar County for trial under the two new indictments.

"She has only served 33 years of her 99-year sentence," LaHood said at a news conference Wednesday in San Antonio. "As I have said before, our focus is to hold Genene Jones accountable for as many children's deaths as the evidence will support.

"For that reason, this will continue to be an open investigation," he said.

Jones worked at what is now called Bexar County Hospital in San Antonio and at a private pediatric clinic in Kerrville in Kerr County in the 1980s. She was sentenced in 1985 for the murder of Chelsea McClellan, 15 months, by injecting her with a powerful muscle relaxant at the Kerrville clinic.

LaHood wouldn't discuss details of the new indictment Wednesday. But after the second indictment was handed up last month, he told reporters: "Babies were taken from their families. Infant children were murdered by what I believe is an evil woman, and that's not going to go unnoticed. These children matter."