The Sofia City Prosecutor's Office has pressed charges against three former directors of the Specialized Directorate Technical Operations of the Interior Ministry (SDOTO), Sergey Katsarov, Kamen Kostov and Tsvetan Ivanov, and one employee of the unit for failure to perform official duties which had serious consequences.

According to a media statement of the prosecuting authority, the current director of SDOTO, Sergey Katsarov has also been charged with document fraud.

Radko Dimitrov, head of a department at SDOTO, has also been charged with committing a crime against justice.

The pre-trial proceedings against the four were opened last week when the prosecuting authority announced the results of a probe conducted on a tip-off of Sergey Stanishev, leader of the Bulgarian Socialist Party (BSP), about illegal wiretapping of politicians, businessmen and magistrates which had taken place during the term in office of former Interior Minister Tsvetan Tsvetanov.

The probe revealed violations which had created possibilities for unregulated wiretapping.

Chief Prosecutor Sotir Tsatsarov declared that the investigation was underway and the work of the former Interior Minister would be examined.

Tsvetanov is is currently being questioned by the Sofia City Prosecutor's Office.

It is believed that he is being questioned in connection with the charges pressed against Bulgarian police's anti-organized crime unit head, Stanimir Florov.

On Friday, Florov, who has close ties with Tsvetanov, was charged with large-scale bribery by the country's prosecuting authority.

Once his first interrogation for the day is over, Tsvetanov is to be questioned by the Specialized Prosecutor's Office in Sofia in connection with the wiretapping scandal.