BULGARIA – CRIMINAL CODE
GENERAL PART
Chapter Four - PUNISHMENT
Section I - General Provisions
Article 37
(2) (Amended, SG No. 153/1998) For the gravest crimes which endanger the foundations of the Republic, as well as for other particularly dangerous deliberate crimes, life imprisonment without substitution shall be provided as provisional and exceptional measure.
National penalties - genocide
National penalties - crimes against humanity
National penalties - war crimes
National penalties - life imprisonment
EDIT.