A daughter will testify against her mother in a murder case involving a woman who was believed to have gone missing — until her remains were found inside a national park in Alabama.

Jessie Eden Kelly, of Union City, Pennsylvania, pleaded guilty Monday in DeKalb County, Alabama, to murder, according to NBC affiliate WAFF. She was originally charged with capital murder in the death of Mary Elizabeth Isbell; as a result of the plea to the lesser charge of murder — which was announced the day her trial was supposed to start — Kelly was sentenced to 40 years in prison.

She is expected to testify against her mother, Loretta Kay Carr, who faces a capital murder charge in Isbell’s death. Carr’s trial is set to start in December.

As Law&Crime has previously reported, Isbell was last seen alive in 2021 and reported missing in December of that year by her ex-husband.

In 2023, Carr, then 45, and Kelly, then 22, faced charges for Isbell’s murder. Prosecutors alleged that Carr killed Isbell by “pushing her off a cliff” inside the Little River Canyon National Park, around 75 miles southeast of Huntsville, causing her death on or around Oct. 18, 2021, Al.com reported, citing an investigator’s affidavit.

The incident occurred “during her abduction or attempt to abduct,” from her home, the affidavit reportedly said, noting signs of a struggle at the victim’s house.

Isbell’s remains were found on June 28, 2023, and were positively identified two days later, on what would have been her 39th birthday.

Her disappearance remained a mystery for years until DeKalb County investigators received credible information in June 2023, leading to Carr and Kelly’s arrests shortly therafter.

DeKalb County Sheriff Nick Wheldon reportedly said that all the women knew each other and appeared to have been connected through someone identified as a “boyfriend.”