You have known Tartaglia since childhood. Recently, his behavior has aroused suspicion and even disgust. he was possessive, especially when you were talking to other guys.

and so, when you were returning home in the evening after a walk, you saw Tartaglia in the alley. his clothes and face were covered in blood, and under his feet lay the bloody body of your classmate with whom you recently talked. He looked at you, and then smiled terribly.