The man who invented the movie camera got on a train in France in 1890 and was never seen again. The wife of Louis Le Prince thought she knew who’d ordered her husband’s disappearance and presumed murder - Thomas Alva Edison. Many people were simultaneously racing to develop moving pictures - so had Edison decided to bump off his closest rival so he could win? The story of who deserves the credit for the movies is a murky one - involving bitter betrayal, courtroom drama and soft-core porn.