Section 17 — Power to investigate crimes
Statutory text (Thai original)
พนักงานฝ่ายปกครองหรือตำรวจมีอำนาจทำการสืบสวนคดีอาญาได้
English translation
Administrative or police officials shall have the power to conduct investigations into criminal cases.
This English translation is provided for reference only and has not yet been firm-verified — always rely on the Thai original.
Firm annotation
Section 17 opens the chapter on the power of investigation and inquiry with the base rule: administrative and police officials may investigate criminal cases. Investigation here is the Thai concept of sueb suan, the fact-finding and detective stage, which the Code treats separately from the formal inquiry (sob suan) governed by later sections. Unlike inquiry, which is tied to territorial jurisdiction, investigative power is broad, but it depends on the officer actually holding office. The section works together with the definitions in Section 2 and with the arrest, accusation, and inquiry provisions that follow.
Why this matters in practice
The key practical point is that investigative authority belongs to a serving official; a suspended or otherwise not-in-office officer has no Section 17 power, which can undermine anything built on their acts. Investigation is also nationwide in reach, so an officer is not confined to the station where they are posted, unlike the territorially limited inquiry power. If your case turns on whether the investigating officer was validly in office or acting within authority, a licensed Thai lawyer can review the appointment and command records.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 5182/2559 (2016)
An officer who has been suspended from duty and is not performing police functions has no power to investigate criminal cases under Section 17 during that period.
Because the first defendant had been suspended from December 2008 until he reported back to duty in August 2010, the Court held that during that gap he was not performing police duties and therefore had no power under Section 17 to investigate or to arrest.
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Supreme Court Judgment No. 13537/2553 (2010)
A police officer has the power under Section 17 to investigate criminal cases; once investigation reveals the details of an offense and identifies a suspect, the officer may lodge an accusation under Sections 2(8), 17, 18, 125, and 127.
The Court held that the officer's acts fell within his authority: as a police officer he had power to investigate the case, and having found the plaintiff to be a suspect connected to illicit fuel trading, he could lawfully lodge an accusation and, once appointed to the investigation team, gather all available evidence.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Frequently asked questions
What is the difference between investigation and inquiry in Thai criminal procedure?
Investigation (sueb suan) under Section 17 is the fact-finding stage and has broad, nationwide reach. Inquiry (sob suan) is the formal case-building process by an inquiry official and is tied to territorial jurisdiction under later sections.
Can a police officer who is suspended from duty investigate a criminal case?
No. Section 17 grants investigative power to serving officials. An officer who has been suspended and is not performing police duties has no power to investigate during that period.