It’s a familiar scene. The hard-boiled detective stares down the cocky suspect, let’s hope they’re not the silent type. interrogation
You have your suspect and they did it, they’re the only one that could have. Right. Your detective has to find out. The challenge, use only dialogue to write the scene. Consider carefully the voice of your characters, their distinctive speech patterns or little sayings. The dialogue needs to feel natural, detectives are often careful about which details of a crime they reveal so make sure they aren’t reeling off long descriptions, less is often more. Is your suspect guilty or innocent? What dealings have they had with the police? A hardened criminal is going to react differently to a model citizen. Consider their reactions carefully, how can you show their character through what they say.
He said/she said is allowed but otherwise everything must be in speech marks.