How long can a criminal case be investigated? This question matters to suspects, their families, victims, and lawyers alike — especially when there are fears that a case is being “dragged out” indefinitely. The answer lies in Article 172 of the Criminal Procedure Code: investigation time limits are divided into four crime categories, with strict caps on the number and length of extensions.
How long does criminal investigation take in Vietnam? (Article 172.1)
The investigation period runs from the initiation of the criminal case until the investigation concludes:
- Less serious crimes: no more than 2 months
- Serious crimes: no more than 3 months
- Very serious and particularly serious crimes: no more than 4 months
Article 172 retains its number and substance through the 2021, 2024, and 2025 amendments to the Criminal Procedure Code (consolidated document 104/VBHN-VPQH 2025). Crime classification follows Article 9 of the Penal Code.
How many extensions, and how long each? (Article 172.2)
Extension requires a complex case; the investigation agency must submit a written request to the procuracy at least 10 days before the time limit expires:
- Less serious: 1 extension, not exceeding 2 months
- Serious: 2 extensions (first not exceeding 3 months, second not exceeding 2 months)
- Very serious: 2 extensions, each not exceeding 4 months
- Particularly serious: 3 extensions, each not exceeding 4 months
Extensions are not automatic: they require the written request 10 days in advance and a decision by the competent procuracy. If the limit expires without extension, the investigation agency must conclude the investigation (issue investigation conclusions, suspend, etc.) — a case may not be left “hanging”.
Special extension (Article 172.3)
For particularly serious crimes where the extension limit is exhausted but the very complex case cannot yet be concluded, the Prosecutor General of the Supreme People’s Procuracy may grant one further extension of up to 4 months. The same applies to crimes against national security.
Who can extend the investigation period? (Article 172.5)
Extension authority was updated under Law 99/2025/QH15 (note: older materials say “district-level procuracy” — since 1 July 2025 authority belongs to the regional procuracy):
- Regional People’s Procuracy: less serious crimes; serious crimes (extensions 1 and 2); very serious crimes (extension 1)
- Provincial People’s Procuracy: cases handled by provincial investigation agencies (less/serious/very serious); very serious crimes (extension 2); particularly serious crimes (extensions 1 and 2)
- Supreme People’s Procuracy: particularly serious crimes (extension 3); cases handled by the Ministry of Public Security, Ministry of National Defence, or the Supreme People’s Procuracy’s own investigation agency
When does the investigation period start?
It starts on the date the criminal case is initiated — not the date of arrest or custody, not the date the act was committed, and not the date a crime report was filed. The verification of crime reports and information is a separate, pre-initiation period under Article 147 of the Criminal Procedure Code: 20 days; complex matters no more than 2 months; one extension of up to 2 months.
Do amended initiation decisions or case mergers “reset” the clock?
No. Article 172.4 provides that where the decision to initiate the case is changed or supplemented, or cases are merged, the total investigation period must not exceed the limits in Article 172.1–172.3. The clock cannot be “reset” by merging or splitting cases.
How does detention pending investigation differ from the investigation period? (Article 173)
These two concepts are frequently confused:
- Investigation period (Article 172): limits how long the investigation agency may investigate the case.
- Detention for investigation (Article 173): limits how long the accused may be held — less serious: up to 2 months; serious: up to 3 months; very/particularly serious: up to 4 months; with separate extension rules (request at least 10 days before expiry). When the detention period expires but the investigation is not finished, the accused must be released or placed under another preventive measure (Article 173.7).
In other words: the detention period may expire while the investigation is still within its limit (switching to another measure such as residence prohibition), and vice versa.
How long do supplementary, reinvestigated, or resumed investigations take? (Article 174)
- Resumed investigation: up to 2 months (less/serious crimes), up to 3 months (very/particularly serious); one extension allowed.
- Supplementary investigation: procuracy returns the file → up to 2 months (the procuracy may return the file only twice); court returns the file → up to 1 month (the presiding judge/trial panel may return it only once).
- Reinvestigation: Article 172 time limits apply again (2–4 months plus 1–3 extensions).
How long do economic crime cases usually take?
Economic crimes typically fall into the serious or very serious categories (high penalty brackets), so the initial investigation period is 3–4 months, extendable as above. Some economic offences carry a “less serious” bracket (up to 3 years’ imprisonment), in which case the limit is 2 months plus one extension.
Note on fugitive suspects: the investigation does not run forever — under Article 229 of the Criminal Procedure Code, when the accused flees, the investigation agency issues a wanted decision and temporarily suspends the investigation (the clock “freezes” until the suspect is caught). See also the topic on extraditing fugitive economic criminals.
Note: the Law on Juvenile Justice 59/2024/QH15 (effective 1 January 2026) may contain separate time-limit rules for juveniles — check that law directly when a case involves a minor.
The information above is for reference only and does not constitute legal advice. Applicable instruments: Criminal Procedure Code 101/2015/QH13, consolidated document 104/VBHN-VPQH 2025 (Articles 147, 172, 173, 174, 229); Penal Code 100/2015/QH13 (Article 9 on crime classification).
For reference only, not legal advice. Content quality-checked by the AI Legal Council; not yet reviewed by a human lawyer.
