You are not allowed to enter here, it's a crime scene. We are investigating now. (Talking to the clueless girl, warning/informing her in a stern tone)

Not everyone shares their concerns... maybe he had a though life himself. (Explaining a possibility with a sympathetic voice)

Hmm.. I feel sorry about your boyfriend. But it's hard to launch an investigation based on what you have just said. (Given up, sadly informing Ellie about the situation with a calm tone)