Chinese police have seized over $15 million in crypto and supercars worth $2 million from the alleged operators of a novel scam that sold counterfeit tokens.

In an article published Thursday, China’s Ministry of Public Security, which oversees the country’s police forces, said police in the city of Wenzhou has arrested 10 individuals suspected of operating the fraudulent scheme.

The criminal case is the first in China where victims were allegedly scammed using blockchain smart contracts to generate fake cryptocurrencies, the ministry said.

Police seized amounts of the bitcoin, ether and tether cryptocurrencies with a total worth of over 100 million yuan, or $15 million. They also seized cars, a Ferrari and a McLaren, was well as luxury villas owned by the suspects.

The case was first reported to the police by a victim, identified by his surname Li, in April. Li had joined a group on the messaging platform Telegram called “Huobi Global Arbitrage HT Chinese Community.”

The group had advertised a blockchain smart contract claimed to be able to generate Huobi Tokens (HT), Huobi exchange’s own cryptocurrency, that could yield an arbitrage opportunity with a return of 8%, the victim said.

“Simply put, you send one unit of ETH to a designated address, you will receive 60 HT. And then you can sell it to gain the difference,” Li reportedly told the police.

The police said in the ministry’s report the price of HT on July 3 was at $4, while ETH was at $227. That created a purported $13 profit for every unit of ETH sent by a victim.

However, after Li sent 10 ETH to the ethereum address provided by the Telegram group’s administrator, the 600 HT he received were fake tokens and could not be deposited for selling, at which point he reported the case to the police.

To be clear, there is no suggestion the Huobi exchange had any involvement with the scam.

The ministry said the suspects created dozens of similar chat groups with over 10,000 fake accounts to make potential victims believe that the scam was a legitimate arbitrage opportunity.

Read more: China Police Said to Detain Crypto OTC Traders Amid Money Laundering Crackdown

After receiving tens of thousands of ether, the police said the main masterminds, Chen, Yu and Xu, who had seven employees working their operation, splashed their gains on an extravagant lifestyle with villas, sports cars and nightclubs.

The police acknowledged this is a new type of crime in China, but did not specify exactly how they located the suspects or if they used on-chain analysis to track down the blockchain transactions that were involved in the case.

In recent months, Chinese police forces have become more experienced in tracking down crypto transactions that may be tainted by illegal activities, such as online gambling, money laundering or economic fraud.

Since June, there have been cases where Chinese over-the-counter traders had their bank accounts frozen due to fiat and crypto transactions being contaminated in this way. Some traders have also been held by police in past weeks to assist investigations.