probably en passant
Resolved: Vanishing act
If it was for move 16 of the game linked below, then yes, it was an "En Passant" capture. Wikipedia it - a lot of people aren't familiar with it when they first start out:-)
http://www.chess.com/echess/game.html?id=53233796
My pawn has done a vanishing act in one of my games. I don't know what happened. Could someone explain? I know it's only a pawn but it's potentially a baby queen. That what i read somewhere anyway hee hee