Published: 2026-06-30

Valuable Source of Information or a Criminal? The Fair Trial and the Institution of the „Key Witness In Sua Causa” in Light of Amendments to Article 60 § 3 of the Penal Code

Mateusz Kazanowski Profil ORCID autora Mateusz Kazanowski
„Młody Jurysta" Czasopismo Studentów i Doktorantów Wydziału Prawa i Administracji Uniwersytetu Kardynała Stefana Wyszyńskiego w Warszawie
Section: Artykuły
DOI https://doi.org/10.21697/mj.17084

Abstract

The article examines the functioning of the institution of the crown witness in the Polish criminal justice system, with particular emphasis on its compatibility with the standards of a fair trial. The aim of the study is to analyse both the procedural and substantive-law forms of this institution, including the so-called “minor crown witness”, as well as to assess the consequences of the 2022 amendment to Article 60 § 3 of the Criminal Code, which significantly strengthened the prosecutor’s position with regard to initiating extraordinary mitigation of punishment. The discussion is to a large extent based on the findings and empirical material presented in the monograph by G. Ocieczek, The Institution of the Crown Witness in Substantive Criminal Law, Criminal Procedure and Empirical Perspective (Warsaw 2023), which allows the theoretical considerations to be confronted with data concerning prosecutorial and investigative practice. The author outlines the genesis of the institution, its axiological justification and the main doctrinal and practical controversies, including threats to the presumption of innocence, equality of arms and the reliability of evidence derived from an offender’s testimony. Particular attention is paid to the assessment of evidence based on denunciation and to the risk of instrumental abuse of this mechanism. The final part formulates conclusions indicating the need for cautious and proportionate use of the crown witness, stronger mechanisms for verifying such testimony and possible legislative changes aimed at enhancing procedural guarantees of the parties.

Keywords:

crown witness, „key witness in sua causa”, credibility of testimony from a crown witness, principles of a fair criminal trial, hearing of evidence

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Citation rules

Kazanowski, M. (2026). Valuable Source of Information or a Criminal? The Fair Trial and the Institution of the „Key Witness In Sua Causa” in Light of Amendments to Article 60 § 3 of the Penal Code. „Młody Jurysta" Czasopismo Studentów I Doktorantów Wydziału Prawa I Administracji Uniwersytetu Kardynała Stefana Wyszyńskiego W Warszawie, (1), 48–60. https://doi.org/10.21697/mj.17084

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