A Chinese national has been convicted of playing a key role in what is believed to be the single largest cryptocurrency seizure in the world, worth more than £5bn ($6.7bn).

Zhimin Qian, also known as Yadi Zhang, pleaded guilty on Monday at Southwark Crown Court, London of illegally acquiring and possessing the cryptocurrency.

Between 2014 and 2017, she led a large-scale scam in China by cheating more than 128,000 victims and storing the stolen funds in bitcoin assets, the Metropolitan Police said in a statement.

A total of 61,000 bitcoins were seized from Qian, the Met said.

The police said the probe began in 2018 after they got a tipoff about the transfer of criminal assets.

Qian had been evading justice for five years up to her arrest, which required a complex investigation involving multiple jurisdictions, said Detective Sergeant Isabella Grotto, who led the Met's investigation.

She fled China using false documents and entered the UK, where she attempted to launder the stolen money by buying property, said the Met.

By pleading guilty today, Ms Zhang hopes to bring some comfort to investors who have waited since 2017 for compensation, and to reassure them that the significant rise in cryptocurrency values means there are more than sufficient funds available to repay their losses, said Qian's solicitor Roger Sahota.

Qian had help from a Chinese takeaway worker named Jian Wen, who was jailed for six years and eight months last year for her part in the criminal operation.

Wen, 44, laundered the proceeds from the scam and moved from living above a restaurant to a multi-million pound rented house in North London, said the Crown Prosecution Service.

Chinese media outlet Lifeweek reported in 2024 that investors, mostly between 50 and 75 years old, had poured hundreds of thousands to tens of millions of yuan into investments promoted by Qian.

Some of the victims were reportedly urged to invest with Qian's scheme by friends and family, knowing little about her.

The case illustrates how cryptocurrency can be exploited by organized crime, demonstrating the necessity for continued vigilance in the digital financial realm.

The investigation is still ongoing, with many victims having some of their money returned by a compensation scheme.

Qian is being held in custody ahead of sentencing, with the date yet to be set.