State Prosecutor Ghassan Oueidat on Monday recused himself from any future role in the investigations into the Beirut port blast.
In a statement, Oueidat said the move aims to avoid any potential conflict of interest arising from the fact that ex-minister Ghazi Zoaiter is married to his sister.
Zoaiter, a former public works minister and current MP, has been charged in the case by Judicial Investigator Judge Fadi Sawan.
The National News Agency said Attorney General Judge Ghassan al-Khoury will now replace Oueidat in the case.
Zoaiter along with caretaker PM Hassan Diab and former ministers Ali Hassan Khalil and Youssef Fenianos have been charged with negligence.