From the website
The leaderships of the Bulgarian Interior Ministry and of the State agency “Archives” announce Friday the final stage of the transfer of police records to the agency........
The police files date from 1923 to September 9, 1944 (the date when Communists took power). The transfer was mandated by an act passed in 2006, aiming at making these records, which have been top secret during the Communist regime and had limited access in the years of transition after 1989, easily available to the public.
Website: Nationaal Archief van Bulgarije ДЪРЖАВНА АГЕНЦИЯ "АРХИВИ"