The sudden death of an expert in the "illegal snooping" case against former Bulgarian Interior Minister Tsvetan Tsvetanov is suspicious and disturbing, according to a former intelligence chief.

Gen Atanas Atanasov from the right-wing Democrats for Strong Bulgaria party, DSB, and former director of the intelligence agency voiced the suspicion Sunday in an interview for the Bulgarian National Radio.

"Some settling of scores in order to cover-up for more serious crimes, including murder, is possible as simple accidents and coincidences are possible as well," said he.

Atanasov stressed that in the past eight years there have been striking examples of eliminations of inconvenient witnesses.

"This is why those in power must be controlled, questioned every day, and forced to provide answers instead of silently avoiding any uncomfortable questions," he explained.

The General made the comments in the aftermath of Saturday reports that an expert's sudden dead has delayed the case against Tsvetanov.

The Bulgarian "Trud" (Labor) daily wrote that Prof Evegeniy Nikolov, who was the expert examining the notorious Chrysler Voyager, allegedly used by Tsvetanov and several subordinates to conduct mass unauthorized spying, has died in a traffic accident on July 17.

Nikolov was the Director of the National Lab for Computer Viruses at the Bulgarian Academy of Sciences, BAS.

The Chrysler Voyager van was seized by the Prosecutor's Office for their probe in the anonymous tipoff of mass illegal spying on senior politicians, wealthy businessmen, and journalists, submitted by the leader of the Bulgarian Socialist Party, BSP, and former PM, Sergey Stanishev.

The Professor was the only expert to have confirmed the vehicle has been, indeed, equipped with spying devices.

He died just one month after Tsvetanov was legally charged with allowing unauthorized mass use of Special Surveillance Devices, SRS.

The probe in the case is still ongoing, and, according to sources from the Prosecutor's Office, the delay is largely attributed to Nikolov's sudden death and the subsequent lack of expert report proving the van has been used for spying.

The former Interior Minister, who is also the Deputy Chairman of the now-opposition, center-right Citizens for European Development of Bulgaria party, GERB, insists he is innocent, stressing the charges are groundless as every former and future Interior Ministry head could face similar ones.

Tsvetanov is also charged on a different count – obstruction of justice.