The mentioned institution is one of the forms of implementation of the principle of publicity in judicial procedure and serves to protect individuals, society, and the state from criminal offenses and is one of the procedural guarantees of the constitutional principles of the rule of law, inviolability, and presumption of innocence of an individual.

In addition, it is an organizational and legal mechanism for: a) ensuring the right to appeal; b) protecting individuals against unreasonable involvement into the sphere of procedural legal relations and their prosecution; c) preventing unnecessary workload imposed on the investigators due to unwarranted commencement of the investigation, wasteful spending of time and money; d) establishing the presence or absence of grounds for commencement of an investigation and execution of tasks stipulated in Art. 2 CPC.

Given that this activity is regulated by CPC, has its own purpose and tasks and the means provided for by law to address the same, and its results are the legal act that empowers the investigator to investigate or refuse from the same, this gives grounds to conclude that it has the signs of an independent stage of the criminal proceedings.

The author argues that in cases stipulated by law when the proceeding ends with its closure and the CPC concept of “closing criminal proceedings” is often used, but does not mention of the commencement of the same, it is contrary to the rules of the logic. In addition, the absence of CPC requirement for the mandatory presence of law defined causes and grounds to commence the proceedings, as well as their content and list of their types, is contrary to the principle of legal certainty and causes the identification of both the commencement of proceedings and commencement of the investigation, as well as their grounds, and even, the very concepts.

The requirement of Part 1 of Art. 214 CPC regarding the commencement of the investigation within 24 hours of receipt of information about the committed offense can not be met in any case, as it is contrary to the requirements of other normative acts and standards of CPC. In particular, before information recording to the Unified Register of Pre-Trial Investigations the need arises to view the place of occurrence as provided for in Part 3 of Art. 214 CPC in addition to view of corpse and forensic medical examination, which according to Art. 238 and 242 CPC are necessary to establish the causes of death. An example of this is the author's study of the current procedure for the commencement of proceedings relating to the establishment of the fact of death of a person.

According to the requirements of Art. 1 CPC the procedure for criminal proceedings on the territory of Ukraine is determined only by the criminal procedural law, and its list of sources does not cover all legal acts, which in fact regulate these legal relations.

The author argues that since the principle of publicity extends to all stages of legal proceedings, it would be correct for Art. 25 CPC, which stipulates this principle, to regulate the commencement of the proceedings, not the investigation as one of its stages, which is a legal act commencing legal relations aimed at conducting judicial procedure and constitutes grounds for commencement of an investigation.

Since the primary information about a criminal offense constitutes the grounds for commencement of proceeding, and is merely the basis for the assessment of whether there is evidence of committed offence or not, then, the assessment of the existence or absence of grounds for commencement of the proceedings would have to be mandatory, and if there is a need for verification, it should be carried out in a manner determined by law within a reasonable time and should be completed by the adoption of a ruling on the commencement of proceedings with information recording to the Unified Register of Pre-Trial Investigations, and in the absence of grounds - a decision to waive the commencement.

The author proposes to distinguish the powers of the prosecutor, the investigator and the head of the pre-trial investigation authority based on the fact that the main function of the investigator is to conduct an objective and impartial investigation. That is why the adoption of such decisions as commencement of proceeding, confirming the indictment, appealing to the court and supporting the prosecution in court should be the sole responsibility of the prosecutor. At the same time, considering the division of the criminal offenses into crimes and criminal offences, and, accordingly, the relative forms of investigation as inquiry and pre-trial investigation, the issues related to the commencement of proceedings concerning criminal offenses would be appropriate to impose upon the head of the investigation authority, and issues related to the commencement of proceedings concerning crimes - upon the prosecutor.

In such circumstances, upon receipt of sources of information about committing the criminal offense, the head of the investigating unit must decide on the expediency of conducting pre-investigation examination and, if it is necessary, to entrust it to the persons concerned. If the available data are sufficient to conclude that the criminal offense has been committed, then he decides to commence the proceedings and entrusts the investigation to a specific investigator. In cases when the materials received have sufficient information about the committed crime, he immediately sends these to the appropriate prosecutor's office for a decision on the commencement of proceedings and organization of an investigation in accordance with the jurisdiction of the crime.

The author argues that neither the detection of signs of a criminal offense (Article 25 of the CPC) nor the identification of circumstances that may indicate his commission of the same (Article 211 CCPC.1) in each case can constitute the reason for commencement of proceedings, since they can not be always the indisputable testimony to its commission.

It is proposed to supplement the CPC with the provisions on the mandatory presence of causes and grounds determined by law, provide their definitions and list, and distinguish in their structure the material and legal and procedural aspects.

The substantive and legal aspect of the above grounds includes: sufficient facts about the committed criminal offense and absence of circumstances determined by law that exclude the crime of the act. Procedural aspect includes: 1) requirements of Art. 2 CPC, which defines the tasks of criminal proceedings; 2) Art. 25 CPC, which obliges authorized persons to take all measures prescribed by law to establish the facts and circumstances of the commission of the offense and person who committed it; 3) the presence of powers in persons determined by law on who deal with these tasks; 4) the decision approved by the authorized person in this regard.

The substantive and legal aspect of the grounds for commencement of investigation is the factual data provided in the reasoning part of the decision to commence the proceedings. Procedural aspect includes: 1) an order to open proceedings; 2) information recorded into the Unified Register of Pre-Trial Investigations; 3) Art. 214 CPC, which obliges, in cases determined by law, to commence an investigation; 4) the commission by the prosecutor (head of the investigating unit) to the investigator regarding investigation conduct; 5) powers of the investigator and absence of obstacles specified by law for investigation conduct; 6) the decision of the investigator on the acceptance of the proceedings for investigation.

The author draws attention to the fact that, even if the commencement of proceedings is not considered as a separate stage of the criminal process, it should be considered as an independent procedural decision, which is the legal act that initiates the specified legal relationship and constitutes legal basis for further procedural actions related to the investigation and judicial procedure. Since the legal status of information recording to the Unified Register of Pre-Trial Investigations is not defined, this fact itself is not a procedural decision, but according to the requirements for the certification of legal facts, the decision to commence proceeding must be distinguished by the features of the relevant procedural document, which would certify the fact of the official initiation of legal relations aimed at the administration of justice and, apart from others, would fulfil the function of a procedural basis for recording this fact to the Unified Register of Pre-Trial Investigations, and initiating an investigation, then, it must comply with the requirements of Part 3, Art. 110 CPC, according to which the decisions of the investigator and the prosecutor are taken in the form of a decision.

The author argues that only the commencement of proceedings is the legal act, which gives the authority to perform the tasks provided for in Art. 2 CPC, and in its absence any investigation is illegal. Given the socio-political and legal significance of the negative consequences of the decision as to the unlawful refusal to commence criminal proceedings in cases of criminal offense and unlawful commencement thereof, the said actions should be criminalized and stipulated in the Code of Criminal Offenses as a crime against justice.

The proposals made regarding the improvement of certain provisions of the Constitution and CPC are outlined in the conclusions of the relevant sections.

Key words: proceedings in a case on criminal offense, pre-trial investigation, legal fact, procedural decision, substantive and procedural grounds.

List of Publications Related to the Topic of PhD Thesis

1. Stelmashchuk O.V. Theoretical and legal analysis of `publicity' reason of a criminal proceeding as determined in the Criminal Procedural Code of Ukraine. Newsletter of the Ministry of Justice of Ukraine, 2016. No. 8. P. 44-48.

2. Stelmashchuk O.V. Signs of a crime as a ground to undertake a criminal proceeding. Newsletter of the Ministry of Justice of Ukraine, 2016. No. 9. P. 58-62.

3. Stelmashchuk O.V., Kotiuk I.I. Topical aspects of a warranty for human rights related to his/her death (problem statement). Review of the Academy of Advocacy of Ukraine, 2016. Vol. 13. No. 3 (37). P. 65-71.

4. Stelmashchuk O.V. Critical weaknesses of a conceptual and categorical framework used in criminal procedural relations. Review of Criminal Procedure, 2016. No. 4. P. 174-180.

5. Stelmashchuk O.V. Circumstances which may witness of a crime as a ground to undertake a pre-trial investigation. Newsletter of the Ministry of Justice of Ukraine, 2017. No. 3. P. 35-41.

6. Stelmashchuk O.V. Undertaking a criminal proceeding as a procedural decision. Review of the Academy of Advocacy of Ukraine: scientific journal, Kyiv: Academy of Advocacy of Ukraine, 2017. Vol. 14. No. 1 (38). P. 112-119.

7. Stelmashchuk O.V. Topical aspects of improvement of criminal procedural relations. Newsletter of the Ministry of Justice of Ukraine, 2016. No. 9. P. 45-50.

8. Stelmashchuk O. Challenges of human rights enforcement under the legal relations stipulated with the person's death (experience of Ukraine). Legea si Viata, 2017. No. 10/2 (310). P. 80-84.

9. Stelmashchuk O.V. Undertaking a criminal proceeding must obligate at all times to verify the availability of appropriate grounds therefor / Topical issues of contemporary civil, international, maritime and transport law: materials of the V International Research-to-Practice Conference, Kyiv: KSWTA, 2015. P. 473-477.