Repair work was agreed but never finished and Derna paid the price. Experts say infrastructure projects have long been neglected, with officials focusing instead on lining their own pockets.
Khalifa Hifter, who oversees a military dictatorship that rules the eastern half of the divided, oil-rich nation, is dominating the response to the disaster and could use it to further entrench his power.
The cries of protesters were part of a rising chorus of calls for answers from leaders across a divided Libya, specifically for an international investigation.