The Lebanese judge investigating the Beirut shipping port explosion Thursday charged caretaker Prime Minister Hassan Diab and three former ministers with criminal negligence for the incident in August which killed more than 200 people, injured thousands more and destroyed large parts of the country’s capital.

Fadi Sawan has charged former public works ministers Ghazi Zaeiter and Youssef Fenianos as well as former finance minister Ali Hassan Khalil. The latter has denied the allegations which he claims are violative of the “constitution and the law”. Outgoing Prime Minister Hassan Diab said that his “conscience was clear” and that he handled the Beirut port explosion transparently and responsibly.

Lebanon saw widespread protests against corruption and official negligence in the aftermath of the blast. In his August resignation speech, Diab referred to being targetted by the opposition for “scoring political points”  and claimed that the system of corruption in the country was “bigger than the State”.

Nizar Saghieh, founder of the advocacy organisation The Legal Agenda, welcomed the move as it means that top officials involved in the incident will no longer be shielded by legal immunity for political acts carried out during office. Many still fear that senior politicians will avoid liability, especially considering that Lebanese officials have rejected calls for an international investigation and Parliament last month declined to act on Sawan’s letter detailing suspicions against government officials uncovered during his investigation.

The US in September had sanctioned Finianos and Khalil for links to Hezbollah, which has now issued a statement calling the measures “politically motivated” and demanding a re-examination of the case.

Sawan is due to interrogate the four men indicted next week; Diab will be questioned at the Prime Minister’s headquarters, Grand Serail, as per Article 85 of the Lebanese Code of Criminal Procedure. Khalil, Zeiter and Finianos will be interrogated at Sawan’s office in the Justice Palace.