Abstract
The purpose of this work is to investigate the circumstances subject to a proof in criminal cases on human trafficking, in order to ensure the effective investigation of criminal cases in this category. The authors propose to classify the circumstances subject to a proof, depending on the elements of offense, based on the analysis of criminal and criminal procedural legislation of the Republic of Kazakhstan and the Kyrgyz Republic, as well as investigation practice of the criminal cases on trafficking in persons. The use of the classification of the circumstances, subject to a proof, submitted by the authors, in the investigation of trafficking in human beings, by the law-enforcement authorities, allows ensuring the comprehensiveness, completeness and impartiality of the investigation and improves the quality of the investigation of such crimes.