portopia renzoku satsujin jiken
"The Portopia Serial Murder Incident / The Portopia Serial Murder Case"
A crime investigation adventure video game designed by Horii Yuuji and published by Enix for the NEC PC-8801 & PC-6001 in 1983. It was ported to the Nintendo Famicom in 1985.
"Yasu is the culprit" (犯人はヤス) is a classic meme that originated from the game's famous spoilers.