In the beginning of the book a boy (think it’s a boy, could be girl) is walking down the street when a newspaper or flyer wraps around his leg. He looks at it and reads the word veni in Latin (I come or I am coming) and smells wet ashes. Later in the book the figure/ghost is beckoning him to jump in a well (?) or off a cliff – he’s saved by someone, but that’s all I remember. Hope you can help.
Edit: The author of this post found the title of the book before I got around to posting their Stumper: The Figure in the Shadows!