WOOD-TV reported that a cause of death wasn't immediately clear and it may take weeks until toxicology results are in.
The trooper discovered the bodies Friday at the Rodeway Inn near Whiteball after responding to a request for a wellbeing check.
Authorities say the baby girl, named Skylah, could have been alone for three days.
Police identified the parents as 26-year-old Jessica Bramer, of Grand Rapids and 28-year-old Christian Reed, of Marne.
警方目前已經確認這對父母分別是來自大急流城的26歲杰西卡·布拉默(Jessica Bramer)和來自馬恩的28歲的克里斯蒂安·里德(Christian Reed)。
Skylah was in critical condition at a Grand Rapids hospital yesterday and was expected to fully recover. It wasn't clear who might take custody of the girl.