A Cash Register Receipt from Fifteen Years Ago

Lin Wanwan, a college student working at a supermarket, stumbled upon an incident from fifteen years ago. There was a case of bottled water on the ground floor, with twenty-four bottles inside. On the side of the case was a row of damp fingerprints. Not five fingerprints, but four. The thumb was missing. A deafening bang went off in Lin Wanwan's mind. She crouched down, her fingers hovering above the prints, afraid to touch them. The droplets had not yet dried completely, and glimmered faintly under the lights. The hand was larger than hers, with thick fingers, like a man's, but it was missing a thumb.