Police in east China's Jiangsu Province confiscated around 4,000 computers used to mine Bitcoin after a local power company reported abnormal electricity usage, local police said Friday.

After nearly two months of investigation, police in the city of Zhenjiang found a criminal gang rented nine factories with installed mining equipment, and arrested 22 people.

A suspect surnamed Lan told police that he bought 10 Bitcoin mining computers in 2017 and made profits in southwest China's Yunnan Province. After that he came to Zhenjiang to continue making money through mining and used theft devices to dodge the power bill.

Each mining computer, depending on the models, used 25 to 50 kw hours of industrial electricity per day, and thousands of computers operating around the clock stole power worth nearly 20 million yuan (around 2.91 million US dollars), according to the power supply company of Zhenjiang.

Bitcoin mining involves heavily power-consuming processes depending on high-performance computers.

The Chinese government has toughened regulation over Bitcoin and other digital cryptocurrency to rein in financial risks, with exchanges closed and trading halted.