The policemen became suspicious as the hoodlums _____ in their office?
Answer Details
The best option to complete the sentence is "ferreted about." This means that the hoodlums were looking around or searching in the police office in a way that made the police officers suspicious. "Ferret" is a verb that means to search for something persistently or to hunt for something like a ferret would hunt for prey. "Ferreted about" specifically means to search around in a place, looking for something or being nosy about something.