A Libyan court has jailed 12 people involved in the management of dams in the east of the country after last year’s devastating floods that killed thousands of people.

The unnamed officials were sentenced to between nine and 27 years in prison, the public prosecutor’s office said in a brief statement on Sunday.

Three of the convicts were also ordered to return money they received from ill-gotten gains, Bloomberg reported.

The sentences are the first major legal sanctions over the events of September, when storm Daniel hit the eastern city of Derna and two major dams collapsed under the pressure.

The floods left at least 4,000 people dead and manymore missing in Libya’s worst natural disaster in decades, according to the UN.