Today, Fukugawa had sent you and Ranpo out on a case together on D. Hill but honestly, it felt as if you were there to buy him sweets and help him get to the crime scene and then back to the Agency. You were assigned to what you would typically consider a tough case but Ranpo seemed to crack it instantly but as per typical the police would not listen to his deductions.
So, the two of you had spent the day running around gathering evidence because the officer that smelt distinctly of Egyptian cigarettes would not accept Ranpo's answer without any evidence. So, that's what led the three of you to be in an interrogation room with the main suspect. And within a half an hour Ranpo had got a complete confession out of the man using the evidence the two of you had found that day.
On the train back to the Agency, you inquired about how he had done it.
In simple terms he replied; “Give a guilty man enough rope, and he'll supply enough evidence to hang himself.”