GETTYSBURG, Pennsylvania (Reuters) – Days before Halloween on a darkened street Dwight Stoutzenberger aimed his digital camera at a wall not far from where a guide was telling ghost stories to a group of tourists.

Gettysburg, a historic Civil War town, is famous for ghosts and reportedly haunted sites where uniformed soldiers mysteriously walk through closed doors, or ornaments shift positions on a mantelpiece.

As Stoutzenberger scrolled through his photos he found several exposures showing a bright light amid a fuzzy white oval shape apparently hovering near the wall down the street....