A South Dakota woman has been convicted Friday of manslaughter in the death of her infant son, whose body was found in a ditch 40-years ago.

The Argus Leader reported that Theresa Bentaas (60) of Sioux Falls entered an Alford plea for first-degree manslaughter. This was in agreement with prosecutors. They also dropped two murder charges. Alford allows Bentaas, 60, to preserve her innocence and also authorizes the court to enter guilty pleas. Bentaas had previously pleaded not guilty.

In Sioux Falls, in 1981, a blanket was found wrapped around a newborn named “Baby Andrew”. He died from exposure, according to an autopsy.

After investigators had reworked this case and found that Bentaas was the mother, police arrested Bentaas.

Mike Webb, a Sioux Falls detective, found that all DNA evidence was destroyed in 1995 according to court documents.

Webb discovered that DNA can be extracted from bone and tissue. Webb exhumed the infant’s body in September 2009. The DNA extracted from the infant’s body by North Texas University Science Center was subject to lab testing, but no matches were detected.

Police submitted DNA from the suspect to a Virginia-based genetics company in 2019. They found two matches.

Police were able to create a family tree that included these genetic links and led them to Theresa Bentaas. According to court documents, investigators discovered DNA in the trash they seized from Bentaas’ house that could not exclude her mother as the biological father.

Bentaas will be sentenced Dec. 2, at the Minnehaha County Courthouse