Extradition and European Arrest Warrant ACT
Chapter two - CONDITIONS FOR EXTRADITION. GROUNDS FOR REFUSAL OF EXTRADITION
Article 7 - Extradition shall be refused:
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6. For a criminal offence, which has been amnestied or in respect of which criminal prosecution or the enforcement of the sentence has been statute-barred under the law of the Bulgarian or of the requesting state;
EDIT.