The newborn was found by a passerby on the side of the road in April 1989

A dead girl found in a roadside box in Minnesota 35 years ago has now been identified – and local authorities will not press charges against the child’s mother.

On Thursday, August 15, the Sherburne County Sheriff’s Office announced that the case of a baby found on April 23, 1989, had been closed. This was reported by several media outlets, including the Associated Press, CBS News and local news station KNSI.

According to AP, the little girl was found by a passerby on the side of the road in Santiago Township and the case remained unsolved for more than three decades.

However, Sherburne County investigators reopened the case last year with assistance from the Minnesota Bureau of Criminal Apprehension and the FBI, and made a breakthrough that led to the identification of the child’s mother, according to CBS News.

The Sherburne County Sheriff’s Office did not immediately respond to PEOPLE’s request for further information on Sunday, August 18.

According to several media reports, a woman, now 56, whose identity has not been released, told authorities that she had kept her pregnancy and the baby’s birth a secret from her family and that the child was not alive at birth. According to AP, police said the mother reacted “in a panic” and “did not know how to handle the situation.”

CBS News, citing Sherburne County officials, said the baby’s 1989 autopsy and a more recent follow-up examination did not determine whether the baby was born alive. The network added that two pathologists now believe the child was likely stillborn.

According to AP, Sherburne County District Attorney Kathleen Heaney dropped the case because the statute of limitations for filing charges had expired.

“Even if the disposal of the child’s body was not in accordance with the law, the statute of limitations has expired and therefore any charges are excluded,” she said, according to KNSI.

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Authorities have since been unable to locate the site where the county coroner’s office originally buried the baby in 1989. The Sherburne County Sheriff’s Office is asking for the public’s help in identifying the location.

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