ALBANY, N.Y. (CBSNewYork/AP) — A New York woman convicted of killing her infant daughter in the 1980s has been granted parole after six failed attempts, state officials said Monday.

State Department of Corrections and Community Supervision officials said Marybeth Tinning, 75, could be released from prison as early as next month. Her release from a Westchester County prison was approved last week after a parole hearing, her seventh since being imprisoned in 1987, officials said in a statement.

A jury convicted the Schenectady resident of killing her ninth child, 4-month-old Tami Lynne, in December 1985. She was the eighth child in the Tinning household to die between 1972 and 1985, CBS2’s Tony Aiello reported.

Marybeth Tinning (credit: New York State Department of Corrections and Community Supervision)

While Tinning was only convicted of killing Tami Lynne, she was suspected in the deaths of six of her other children. Authorities believe the couple’s first child died of natural causes.

Marybeth Tinning was convicted of murder in 1987 for smothering Tami Lynne. Tinning was sentenced to 20 years to life and entered the medium-security Taconic Correctional Facility in Bedford Hills that October. She was denied parole six previous consecutive times, starting with her first parole hearing in March 2007.

Tinning denied killing any of her children, including Tami Lynne, but that began to change during her second parole hearing in January 2011.

“After the deaths of my other children … I just lost it,” Tinning told the parole board, according to the Times Union of Albany. “(I) became a damaged worthless piece of person and when my daughter was young, in my state of mind at that time, I just believed that she was going to die also. So I just did it.”

Some experts believe Tinning suffered from the mental disorder Munchausen syndrome by proxy, and say her case helped encourage hospitals, police, and medical examiners to better communicate with each other in suspicious matters involving children.

The Tinnings lived in Schenectady, where Joseph worked at the General Electric’s turbine manufacturing plant. His wife worked part-time jobs, including as a school bus driver and waitress.

Three of the couple’s three children — 8 days old, 2 years old and 4 years old — died within a two-month span in early 1972. Authorities determined the infant girl died from acute meningitis and didn’t consider her death suspicious. Marybeth Tinning attributed the other two deaths to seizures. Investigators looked into the death of the 4-year-old but dropped the case after doctors attributed his death to cardiac arrest.

The fourth child’s death just two weeks after birth in 1973 was attributed to sudden infant death syndrome.

The death in 1975 of a 5-month-old boy was attributed after an autopsy to acute pulmonary edema. His death was followed four years later by that of a 3-month-old girl, who was said to have died of SIDS. The cause of death of a 3-month-old son in 1980 was undetermined, while the 1981 death of a 3-year-old boy the couple was in the process of adopting was blamed on bronchial pneumonia.

While local doctors and pathologists at the hospitals where the Tinning children had been taken had grown suspicious by then, charges weren’t brought against Marybeth Tinning until Tami Lynne’s death.

Under questioning by state police investigators in early 1986, she admitted to smothering the girl as well as two of her sons. Prosecutors indicted her for the three deaths, with the lone conviction coming in the case of Tami Lynne’s killing.

Paul Callahan, Tinning’s trial attorney, said he was glad for her impending release.

“There’s going to be an adjustment period for her, and who knows how long that will be?” Callahan told The Daily Gazette, the first to report her parole. “But she’ll wake up in the morning, walk around and do what she wants to do.”

Her husband, who was never implicated in any of the deaths, told the newspaper he is “very glad that it will soon be all over with.” He said she expects her to live with him in Duanesburg, a rural town outside Schenectady. Messages left by The Associated Press at a number listed for him weren’t returned.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)