A principal who set up a secret cryptocurrency mining operation in his school has been sacked after teachers noticed a whirring sound coming from the computer room.
According to the BBC, Lei Hua, a headmaster at Puman Middle School in Chenzhou, Hunan Province, was let go after he was found to mining ethereum on school grounds.
Mr Hua managed to rack up a 14,700 yuan ($ A2940) electricity bill after using the school's power to run the mining machines day and night.
• Australia's billion-dollar rort
• City making homeowners rich
• 'Risky move' a million-dollar business
Mr Hua began mining the cryptocurrency at home in a bid to make some extra money on the side, but the device was chewing through 21 kilowatt-hours of electricity a day.
He moved the computer to the school, and added a more "miners" to his operation.
He is also a member of the Wang Zhipeng group.
Mr Hipe was sacked last month, while Mr Zhipeng was allowed to keep his job after being given an official warning.
The BBC claimed Mr Hua had already been warned about the school's unusually high power bills, which he claimed to be used for cooling and heating in classrooms.
But eventually, teachers noticed a constant whirring noise, which led to the discovery of the machines.
Apparently, the mining scheme also has overloaded the school's computer network and caused slow downs, which affected teachers' ability to do their jobs.
According to Caixin Global, cryptocurrency "miners" work by solving "the mathematical puzzles that power a cryptocurrency's network".
They are then awarded "coins" of the virtual currency, which can be converted to "hard" currencies.
However, the process also requires a great deal of electricity, which Mr Hua and Mr Zhipeng were caught.
It is not known how much the men made from their schemes, although Chinese media revealed their profits had been seized by China's disciplinary commission.
Cyber-security expert Matthew Hickey told the BBC the educators' scheme would have been obvious.
"The noise and heat of the nine actively running mining machines would have been very noticeable," he said.