Iliya Iliev, who was the secretary general of Bulgaria's Interior Ministry until November last year, was arrested on March 25 2008 on charges of overstepping his authority, Dnevnik daily reported.

The military prosecutors declined to comment whether the arrest was related to the arrest of alleged Montenegrin-born drug boss Budimir Kujovic or for authorising the start of the investigation against former deputy chief of the Chief Directorate for Combating Organised Crime Ivan Ivanov, arrested last week on charges of leaking confidential information about ongoing investigations.

Appointed in 2005 and widely seen as one of the closest allies of Interior Minister Roumen Petkov, Iliev resigned on November 28 2007, after being "grossly misled into signing a document about an Interior Ministry operation which in a way did not correspond to ministry regulations".

At that time, it was speculated that he was referring to the Kujovic case, in which the alleged drug dealer was issued a Bulgarian residence permit despite a standing ban on him entering the country.

But it appears that the reason might have been sanctioning the use of wire-tapping devices in the investigation against Ivanov, which Iliev was not authorised to do, despite being the top official at the ministry, mediapool.bg claimed. The use of wire-tapping devices can only be requested by the Interior Minister, according to Bulgarian laws.

Ivanov was been by the Sofia military prosecutors on the evening of March 17, allegedly for reporting to businessmen about police investigations against their firms.