Nevada-tan (ネバダたん, Nebada-tan), is the name commonly used to describe an 11-year-old Japanese schoolgirl who was charged with murdering her classmate Satomi Mitarai (御手洗 怜美, Mitarai Satomi). The murder occurred on June 1, 2004 at an elementary school in Sasebo, Japan and involved the slitting of Mitarai's throat and arms with a box cutter. It has come to be known as the "Sasebo Slashing". The unnamed killer (real name undisclosed by police for privacy reasons but fully broadcasted by Fuji TV while showing her drawings) has since become an internet meme cartoon character.
Nevada-tan's "name" comes from the University of Nevada hooded sweater she was wearing at the time.