S1·E583 The Love of Kobayashi-sensei

Kobayashi insists on escorting the Detective Boys to the fireworks festival after hearing about a series recent robberies. Kobayashi becomes lost on the way when they decide to take a shortcut and witnesses a feud between two people in an alleyway which results in one of them being stabbed to death. At the police station, Shiratori questions Kobayashi about the murder of the woman named Akira Sumida. Kobayashi explains she heard a female voice threatening to kill the other in the midst of the argument. She adds on that the culprit was likely female due to her breasts and she saw a truck with the partially covered number 09 across the alley. Kobayashi leaves to go to the washroom when she overhears some officers mentioning how Shiratori may be dating Kobayashi only because she resembles Sato and is heartbroken.