Final answer:
The detectives might need the dress for a date, a dance, or an evening out in order to investigate a case or gather evidence. They may use disguises or costumes to blend in and gain access to certain situations or locations, allowing them to gather information without drawing attention to themselves.
Step-by-step explanation:
The detectives might say they need the dress for a date, a dance, or an evening out in order to investigate a case or gather evidence. In many detective stories and crime dramas, detectives often use disguises or costumes to blend in and gain access to certain situations or locations. By wearing the dress, the detectives may be able to infiltrate a specific event, gather information, or observe suspects without drawing attention to themselves.