a. Nature

Nature of Preliminary Investigation

Concept

Preliminary investigation is a summary, inquisitorial proceeding to decide whether a respondent should be charged in court and held for trial. It is not a trial of guilt. The prosecutor evaluates the evidence for a basis to proceed; factual disputes and guilt beyond reasonable doubt are left for trial. (Sec. 7, 2024 DOJ-NPS Rules on Preliminary Investigations and Inqu…)¹ (Lima v. Reyes, G.R. No. 209330, 11 January 2016)² (Ampatuan v. Justice, G.R. No. 200106, 22 February 2023)³

Governing provisions

Rule 112 defines preliminary investigation as an inquiry into whether sufficient ground exists for a well-founded belief that a crime was committed and the respondent is probably guilty. Subject to its section 6 exception, it requires preliminary investigation before filing a complaint or information for an offense carrying a prescribed penalty of at least four years, two months, and one day, regardless of the fine. (Rule 112, Sec. 1, Rules of Court)⁴

The 2024 DOJ-NPS Rules describe preliminary investigation as a summary proceeding based on the evidence provided, after case build-up where necessary, to ascertain prima facie evidence with reasonable certainty of conviction. They expressly adopt an executive and inquisitorial approach and a proactive prosecutorial role. Inconsistent provisions of Rule 112 are deemed repealed following the Court’s recognition of the DOJ’s authority to issue those rules. (Sec. 7, 2024 DOJ-NPS Rules on Preliminary Investigations and Inqu…)¹ (Sec. 4, 2024 DOJ-NPS Rules on Preliminary Investigations and Inqu…)⁵ (Re: Draft Department of Justice-National Prosecution Service'S [dojnps] Rules on Preliminary Investigations, A.M. No. 24-02-09-SC, 28 May 2024)⁶

Requisites / Rules

• Under Rule 112, the investigating prosecutor who finds cause to hold the respondent for trial prepares a resolution and information. The information must carry the prescribed sworn certification, including that the respondent was informed of the complaint and evidence and had an opportunity to submit controverting evidence. Otherwise, the prosecutor recommends dismissal. (Rule 112, Sec. 4, Rules of Court)⁷
• An investigating prosecutor may not file or dismiss a complaint or information without the prior written authority or approval specified in Rule 112. The resolution and record are forwarded for action by the designated reviewing official. (Rule 112, Sec. 4, Rules of Court)⁷
• The DOJ-NPS Rules allow a virtual preliminary investigation as an alternative at the initial hearing when both parties are present and the necessary information and communications technology is available to the prosecution office and the parties. (Sec. 7, 2024 DOJ-NPS Rules on Preliminary Investigations and Inqu…)¹

Distinctions

The prosecutor’s determination concerns whether to charge the respondent. A judge independently makes the judicial determination relevant to an arrest warrant after an information is filed. The trial court does not act as an appellate reviewer of the prosecutor’s determination. (People v. Omelio, G.R. No. 229705, 14 July 2021)⁸ (Mendoza v. People, G.R. No. 197293, 21 April 2014)⁹

Key doctrines

Preliminary investigation and inquest fall within the prosecutorial, executive function. The Court has recognized DOJ rule-making in this area while retaining its authority over court procedure and its power to correct prosecutorial action involving grave abuse of discretion. Judicial review of a preliminary-investigation determination does not entail deciding probable cause anew. (Re: Draft Department of Justice-National Prosecution Service'S [dojnps] Rules on Preliminary Investigations)⁶ (Meking v. Remulla, G.R. No. 280455, 11 November 2025)¹⁰ (Ampatuan v. Justice)³

Exceptions

For a lawful warrantless arrest involving an offense requiring preliminary investigation, Rule 112 permits filing without that investigation if an inquest has been conducted. It also provides ways for the arrested person to request preliminary investigation before filing, subject to a counseled waiver, or within five days after learning of a filing made without preliminary investigation. (Rule 112, Sec. 6, Rules of Court)¹¹

Bar tip

Identify the decision-maker and the stage: the prosecutor decides whether to charge; after filing, the judge independently addresses judicial probable cause. Do not treat preliminary investigation as a trial on guilt. (People v. Omelio)⁸ (Lima v. Reyes)²