A group of hackers has allegedly colluded with computer maintenance firms in China to hack into computers owned by internet cafes to mine cryptocurrency.

According to a local news report on Saturday, police in Rui'An city in Zhejiang province arrested 16 suspects who, it's claimed, have gained 5 million yuan ($800,000) by hacking more than 100,000 computers in internet cafes across 30 Chinese cities since July of last year.

The report said the hackers first developed a piece of malware that can specifically mine the siacoin cryptocurrency on an affected device, then marketed it to computer maintenance firms who allegedly helped to inject the malware to computers at internet cafes whilst carrying out routine checkups.

The profits made by mining and selling the siacoins would then be split among the hackers and their alleged accomplices, the report said.

The issue emerged in July 2017 when internet cafes in Rui'An started to notice their computers had become extremely slow, since the CPU usage rate was often at 70 percent even after a restart.

Notably, it was also at a time when the price of siacoin jumped by 400 percent from $0.002 in May to over $0.01 in July, data from CoinMarketCap shows.

Meanwhile, the utility bills of the affected internet cafes in Rui'An also went up significantly during that period, the report said. Subsequently the owners reported the case to the local police.

Since most internet cafes in Rui'An used the same computer maintenance firm (which was unnamed in the report), the police arrested the firm's chief executive officer in August, who later revealed information on the hackers.

Currently, the investigation is still ongoing, since the malware has now spread across more than 30 cities in China, with over 100 computer maintenance firms in the country being allegedly involved.

Internet cafe image via Shutterstock