For a few moments, the sight could have been confused for a miraculous arrival ahead of the Christmas season: A newborn baby, hours old and full term, appeared within a nativity scene at a Queens church on Monday.

But the story of how the baby got onto the stage inside the Holy Child Jesus Church in the Richmond Hill neighborhood was much more earthly, the police said: A woman, seen on video, had arrived with the boy wrapped in a towel, his umbilical cord still attached, and departed without him.

On Tuesday afternoon, detectives were seeking to speak with the woman, who was believed to be the child’s mother.

Late Monday morning, a custodian, Jose Moran, arranged the empty manger at the front of the church, facing the pews, the crèche still empty of all the animals and statues of the Christmas story. Then he went to lunch.