The Czar's Spy by William le Queux

That day was an active one in Questura, or police office, of Leghorn.

Detectives called, examined the safe, and sagely declared it to be burglar-proof, had not the thieves possessed the key. The Foreign Office knew that, for they supply all the safes to the Consulates abroad, in order that the precious ciphers shall be kept from the prying eyes of foreign spies. The Questore, or chief of police, was of opinion that it was the ciphers of which the thieves had been in search, and was much relieved to hear that they were in safekeeping far away in Downing Street.