Sofia's City Court adjourned the trial against Bulgarian Former Interior Minister Tsvetan Tsvetanov until May.

The decision was announced after the only witness to be heard over the case failed to appear in court, the website Dariknews.bg has reported.

Tsvetan Ivanov could not attend due to hypertension.

The court however stated that this reason was not cogent enough and Ivanov should be forced into the next sitting on May 13.

Ivanov was formerly head of the Specialized Operative and Technical Information Directorate (SDOTO), which until last year was part of the Interior Ministry and which administered wiretapping.

Tsvetanov is now facing charges of blocking six permits to use special surveillance devices against Orlin Todorov, former head of the Interior's Chief Directorate Combating Organized Crime(GBDOP) in Veliko Tarnovo.

In February, a session was again postponed after defense counsel Menko Menkov was reported to have a respiratory problem.

Two more trials are under way against Tsvetanov over large-scale embezzlement and allowing unauthorized wiretapping.

The former Interior Minister has repeatedly insisted on the "political nature" of the trials.

Tsvetanov nevertheless agreed to be stripped of his immunity as lawmaker in order to face all charges.