Who found out who wrote the messages Haunting at Home Plate?

In the mystery surrounding "Haunting at Home Plate," it was ultimately revealed that the messages were written by the character of Billy, a former player who expressed his feelings and experiences through the notes. The discovery of his identity added depth to the story, as it highlighted themes of loss and unresolved emotions tied to the world of Baseball. The revelation also served to connect the past with the present, illustrating the impact of history on the characters' lives.