Police have seized a Cartier diamond ring worth more than £1m bought by a jailed Azerbaijani banker in Harrods, the latest move in the UK’s first McMafia-style “dirty money” investigation.

A district judge on Monday granted the confiscation of the ring worth £1,190,000, plus VAT, that Jahangir Hajiyev obtained from at the department store in London’s Knightsbridge in 2011. The National Crime Agency (NCA) seized the ring from a high-end London jewellers, where it had been taken for repairs.

The ring is presumed to have been bought for Hajiyev’s wife, Zamira Hajiyeva, who is the subject of the NCA’s first unexplained wealth order (UWO). Hajiyeva has refused requests to explain the source of her extraordinary wealth. If she continues to fail to reveal the origin of her fortune, the courts could seize her properties including a £11.5m five-bedroom home in Knightsbridge and a £10.5m golf and country club in Ascot.

It was revealed in the high court last year that Hajiyeva, whose main home is less than 100 yards from the doors of Harrods, had spent £16,309,077.87 there in over a decade. The NCA said she used 35 credit cards issued by her husband’s bank to fund the spending spree at the shop.

The court also heard that she had access to a $42m (£33m) Gulfstream G550 jet and had a wine cellar stocked with some of the world’s most expensive bottles.

The 8.9-carat Cartier diamond ring was seized under the “listed assets” provisions introduced by the Criminal Finances Act 2017. The NCA said: “The source of the funds to purchase the jewellery requires further investigation.”

The NCA seized £400,000 worth of Hajiyeva’s jewellery in November from Christie’s auction house in central London, where they had been brought to be valued by Hajiyeva’s daughter, Leyla Mahmudova. The agency said the source of funds used to purchase the jewellery, including a £120,000 Boucheron sapphire and ruby necklace, “requires further investigation”.

The NCA claims Hajiyeva is wanted by Azerbaijani authorities in connection with avoiding the investigation into fraud at her husband’s former bank. She is one of several family members whom the authorities claim were used by Jahangir to take money out of the country.

The family denies the allegations. In October, Hajiyeva’s lawyer said: “The decision of the high court upholding the grant of an [UWO] against Zamira Hajiyeva does not and should not be taken to imply any wrongdoing, whether on her part or that of her husband. The NCA’s case is that the UWO is part of an investigative process, not a criminal procedure, and it does not involve the finding of any criminal offence.”