Former Bulgarian Interior Minister Tsvetan Tsvetanov was sentenced to four years in jail on Thursday on charges of impeding justice, the Sofia city court announced.
Tsvetanov -- who served as a minister in the conservative cabinet of ex-premier Boyko Borisov between 2009 and 2013 -- is still Borisov's right-hand man and a powerful figure in his opposition GERB party.
He was however embroiled in several scandals and is also facing charges for the alleged wiretapping of top politicians and businessmen.
The court ruled on Thursday that Tsvetanov had disregarded his duties and thwarted a probe against the now retired chief of the interior ministry's anti-organised crime unit Stanimir Florov and several of his subordinates.
The suspects were accused of having facilitated and protected contraband and drug smuggling in exchange for bribes.
Tsvetanov thwarted the probe against them by refusing several wiretapping requests against one of Florov's subordinates embroiled in the scheme.
The sentence can still be appealed to a higher instance court.
Sofia's city court will meanwhile start hearing on Friday the illegal wiretapping case against Tsvetanov.
According to prosecutors, his feeble control over his ministry's surveillance and wiretaps unit allowed the illegal bugging of political opponents, businessmen and journalists during his time in office.
If found guilty on the second set of charges, the powerful ex-minister faces between one and eight years in jail.