The mother of a baby who was abandoned in a gravel pit and found dead in Maine more than 35 years ago is expected to plead guilty to manslaughter.

According to CBS 13, police arrested Lee Ann Daigle, formerly Lee Ann Guerrette, of Lowell, Massachusetts in June and originally charged her with murder.

According to court documents, she will plead guilty to manslaughter in Houlton on Thursday.

In Dec. 1985, the newborn was found in Frenchville by a neighbor’s dog, which carried the baby back to its home.

State police credited Daigle’s arrest to decades of work by dozens of current and retired detectives and advancements in DNA technology and genealogy.