The missed clue in In-ho’s dorm
In episode 2, detective Jun-ho visits his brother In-ho’s dorm to check on him after receiving a phone call from his concerned mother. He discovers that In-ho hasn’t been there for a while and hasn’t paid his rent on time, leaving him owing money. His two fish are also dead.
He spots a black box with a pink ribbon while rummaging through the rubble. It’s a clue, but he isn’t aware of it at the time. Later in the game, he’ll see that box in the form of coffins again.