Experts have warned about the structural integrity of the twin dams in Derna for years, a Libyan state prosecutor revealed.

Concerns have been raised since 1986 when the dams suffered major damage in the wake of a wild storm.

Libya’s general prosecutor al-Sediq al-Sour said that more than a decade later, a study was commissioned by the Libyan government that revealed cracks and fissures in the dam structures.

Turkish firm Arsel Construction Company was also contracted in 2007 to maintain the two dams and to build a third damn in between them.

The firm’s website claims the works were completed in November 2012 but, according to recent satellite photos, no third dam was built.

Arsel did not respond to an email seeking further comment on the two dams.

In 2012 and 2013, 2 million dollars was set aside to maintain the twin dams.

But, according to a report by a state-run audit agency in 2021, the two dams were never maintained.

The audit agency has since blamed the Ministry of Works and Natural Resources for failing to cancel the contract and give it to a company that would do the work.

Mr Al-Sediq al-Sour said in a press conference on Friday that prosecutors would investigate the collapse of the two dams and the allocation of maintenance funds.

He said: “I reassure citizens that whoever made mistakes or negligence, prosecutors will certainly take firm measures, file a criminal case against him and send him to trial.”

After decades of neglect and heavy rains caused by Storm Daniel, the two dams in Derna were overwhelmed on September 12.

A wall of water razed the city, killing at least 11,000 people and destroying entire neighbourhoods in the process.

The Libyan Red Crescent says more than 10,000 people are still missing.

The North African nation has been in chaos since 2011, when an Arab Spring uprising, backed by Nato, ousted dictator Muammar Gadhafi, who was later killed.

The country has since divided between rival administrations: one in the west backed by an array of lawless armed groups and militias, and the second in the east allied with the self-styled Libyan National Army, which is commanded by powerful General Khalifa Hifter.

Ahead of Mediterranean storm Daniel, authorities gave contradicting messages. They imposed a curfew in Derna and other areas in the east. The municipality of Derna published statements on its website urging residents to evacuate the coastal areas for fear of a surge from the sea.

However, many residents said they received text messages on their phones urging them not to leave their homes.

Activists are calling for an international probe, fearing that a local investigation would be fruitless in a country largely ruled by armed groups and militias.

The “predatory” behaviour of these groups and militias has resulted in “the misappropriation of Libyan State funds and the deterioration of institutions and infrastructure”, according to a report by a UN panel of experts.

Libya has suffered from weak public institutions, internal conflict and deep instability, which allowed corruption to become rife with few to no checks on public sector abuse, according to Transparency International.

An online petition signed in recent days by hundreds of people, including Libyan rights groups and NGOs, said an independent international committee is needed to “uncover the causes of this catastrophe” and hold those responsible accountable.

Jalel Harchaoui, an expert on Libya at the London-based Royal United Services Institute for Defence and Security Studies, said an investigation into the disaster would face towering challenges since it could reach top officials in west and east Libya.

Such an inquiry “might potentially reach into the highest ranks of responsibility”, he said. “This presents a unique challenge.”