LONDON — The wife of an Azerbaijani banker dropped 30,000 pounds on chocolate in one purchase, amassed £3.5 million of designer French jewelry, and spent more than £150,000 on perfume.

And that was just at one store.

The extravagant spending by the woman, Zamira Hajiyeva, at the luxury British department store Harrods — which amounted to around £16 million pounds, or more than $20 million, over a decade — and other purchases made by her and her husband, Jahangir Hajiyev, raised one big question: Where did all that money come from?

The British authorities, who have been trying to clean up Britain’s reputation as a haven for “dirty money,” now have a tool to find the answer: an unexplained wealth order.

The order can require individuals to account for their wealth, and Ms. Hajiyeva had the unwelcome distinction last year of being the first person subject to one. This week, a second unexplained wealth order was issued for three London properties worth tens of millions of dollars that are linked to an unnamed “politically exposed person” — or a person whose prominent position in public life may make them vulnerable to corruption — and who is believed to be involved in serious crime, the national crime agency said Wednesday.