(AP) — The South Dakota Department of Corrections says a woman convicted last year in the 1981 death of her newborn son has been released on parole after serving less than three months in prison.

Theresa Bentaas, 60, was granted parole March 17, but was not immediately released. In a notice Monday, corrections officials said Bentaas was freed. The case of the infant’s death remained unsolved until 2019 when advances in DNA technology led investigators to Bentaas.

She entered an Alford plea to a first-degree manslaughter charge last October. The plea means she maintained her innocence but admitted that evidence could persuade a judge or jury of her guilt.