Varna Mayor Blagomir Kotsev and the two municipal councilors - Yordan Kateliev and Nikolay Stefanov - were summoned today to present the materials of the investigation.
On Monday, the three of them were presented with new charges.
Kotsev's media advisor Antoaneta Petrova has also joined the accused.
The first charge against them has been clarified.
They are no longer part of an organized criminal group, but are accused of criminal association.
The investigation is in its final stages and after the accused make their objections and requests, the prosecutor's office should consider whether to file an indictment with the court.