Anticorruption prosecutors have accused Dragnea of using his authority and political influence as head of the Teleorman county council to secure a massive voter turnout in the county that would guarantee the validation of vote results.
Dragnea has repeatedly denied any wrongdoing.
Alongside Dragnea, 67 other people are investigated over alleged fraud at the 2012 referendum on the impeachment of President Traian Basescu, including heads and members of polling stations in counties Teleorman, Vrancea, and Gorj, observers on behalf of NGOs, and party members.
The case regarding the 2012 referendum was built by anticorruption Lucian Papici, who was fired on October 2 from his position of National Anticorruption Department section chief.