Abstract
The situation with the powers of pre-trial investigation officers in Lithuanian criminal proceedings has not changed for more than two decades, so this necessitates the need to systematically analyse the limits of the procedural autonomy of the pre-trial investigation officer at the pre-trial investigation stage, as well as possible levers that encourage this subject of criminal proceedings to strive for the quality and efficiency of criminal investigation. Therefore, the purpose of this research paper is to analyse the possibilities of regulating the procedural status of the pre-trial investigation officer and expanding it in Lithuanian criminal process, in order to optimize and accelerate the pre-trial investigation. So, this study aims to analyse the possibilities of expanding the procedural functions of the pre-trial investigation officer in three different areas of pre-trial investigation in Lithuanian criminal proceedings: in the area of initiating procedural investigative actions that are sanctioned by the pre-trial investigation judge, in the area of imposing milder preventive measures and temporary restrictions on property rights, and in the area of making final procedural decisions summarizing the pre-trial investigation. The research was carried out by employing the document analysis, the systematic analysis, the deduction analysis and the generalization method. The results of research analysis objectively substantiated the real possibilities and need to expand the functions of the pre-trial investigation officer in these areas of pre-trial investigation.