BULGARIA – CRIMINAL CODE
GENERAL PART
Chapter Four - PUNISHMENT
Section II - Kinds of Punishments
Article 38
(1) The punishment life imprisonment without substitution, provided in the Special Part hereof for a certain kind of crime, shall be imposed only if the specific crime committed was extremely grave and the purposes set forth in Article 36 hereof could not be attained by any milder punishment.
Crimes against humanity
Genocide
War crimes
National penalties - life imprisonment
EDIT.