Commercial Bank of Ethiopia has lost more than £31 million after a technical glitch let customers withdraw and transfer money that was not in their accounts.
The state-owned bank was hit by a systems failure which lasted for several hours over the weekend. A cyber-attack has been ruled out.
Customers took advantage to make ATM withdrawals and money transfers, making off with more than £31 million, according to the BBC.
The bank has assembled a task force as it seeks to recoup the money, with some students on university campuses already detained, says the BBC.