A New York company turned a former coal plant into a gas-fired Bitcoin mine. Environmentalists have been critical - but the company says it offsets its emissions.
Officers had seized more than 1,000 Bitcoin mining units allegedly powered by stolen electricity.
By Mary-Ann Russon
Business reporter, BBC News
By Nduka Orjinmo
BBC News, Abuja
By Chris Vallance
China has told banks and payments platforms to stop supporting digital currency transactions.
Tanzanian President Samia Suluhu Hassan has urged the country's central bank to be prepared for the use of digital currencies.
President Samia told the Bank of Tanzania on Sunday to be vigilant amid a rising interest and adoption of cryptocurrencies around the globe.
"I know that many countries around the world have not accepted or started using digital currencies. However, I call upon the Bank of Tanzania to start looking into these developments just to be prepared.
"We don't want to be caught unawares or find out later that our citizens are ahead of us and have already started using cryptocurrencies," she said.
El Salvador last week became the first country in the world to officially classify a digital currency, Bitcoin, as legal currency.