Section 122: When investigation may be declined
Statutory text (Thai original)
พนักงานสอบสวนจะไม่ทำการสอบสวน ในกรณีต่อไปนี้ก็ได้
(๑) เมื่อผู้เสียหายขอความช่วยเหลือ แต่ไม่ยอมร้องทุกข์ตามระเบียบ
(๒) เมื่อผู้เสียหายฟ้องคดีเสียเองโดยมิได้ร้องทุกข์ก่อน
(๓) เมื่อมีหนังสือกล่าวโทษเป็นบัตรสนเท่ห์ หรือบุคคลที่กล่าวโทษด้วยปากไม่ยอมบอกว่าเขาคือใคร หรือไม่ยอมลงลายมือชื่อในคำกล่าวโทษหรือบันทึกคำกล่าวโทษ
English translation
An investigating officer may decline to conduct an investigation in the following cases: (1) when the injured person requests assistance but refuses to lodge a complaint in accordance with the regulations; (2) when the injured person files the case himself without having first lodged a complaint; (3) when the accusation is made by an anonymous letter, or the person making an oral accusation refuses to say who he is, or refuses to sign the accusation or the record of the accusation.
This English translation is provided for reference only and has not yet been firm-verified. Always rely on the Thai original.
Firm annotation
This General Principles provision gives the investigator a discretion, not a duty, to decline investigation in three defined situations. It is permissive: the word used means the officer may decline, so it does not bar investigation in those cases. The provision works alongside the complaint and accusation rules in Sections 123 to 127, and the anonymous-letter ground in (3) mirrors the accusation rule in Section 127. Read correctly, it lets officers avoid being drawn into matters where the injured person will not cooperate, while leaving room to investigate serious anonymous tips.
Why this matters in practice
If you are the injured person, the practical lesson is to file a proper, signed complaint: an officer who is only given an anonymous or unsigned accusation, or a request for help with no complaint, may lawfully decline to act. But note this is a discretion, not a prohibition, so police can still investigate an anonymous tip about a serious crime if they choose. If your complaint is being turned away, it is worth checking whether it was made correctly. Our guide on what to know before going to court in Thailand explains the wider process.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 273/2498 (1955)
Section 122 is not an absolute prohibition against an investigating officer acting on an anonymous accusation letter; the officer retains discretion to investigate.
In a case charging an official with unlawfully receiving money, the Supreme Court held that Section 122 does not absolutely bar an investigator from investigating on the basis of an anonymous accusation letter, so the investigation was not invalid on that ground.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Cited in 9 Supreme Court decisions (1955 to 2011)
Selected citing decisions
- Decision 4973/2549 (2006)
- Decision 7427/2541 (1998)
- Decision 1491/2540 (1997)
- Decision 273/2498 (1955)
- Decision 1265/2554 (2011)
- Decision 1537/2541 (1998)
- Decision 2825/2543 (2000)
- Decision 6701/2541 (1998)
This list is selected automatically, weighted towards judgments that turn on this section rather than ones that merely recite it when passing sentence. It has not yet been reviewed by the firm.
Most often cited alongside
- Section 221 8
- Thai Penal Code s. 75 5
- Thai Penal Code s. 78 4
- Thai Penal Code s. 83 3
- Thai Penal Code s. 91 3
Sections that appear in the same judgments as this one most often. The figure is the number of decisions.
Counted across the firm's corpus of 83,652 Supreme Court decisions, 1921 to 2026. The count is complete; the stated year range trims rare outliers so it describes where the citations actually sit. These figures are computed by us and are not official court statistics. How we count these, and what we measured
Frequently asked questions
Can police refuse to investigate an anonymous tip?
They may. Under Section 122(3) an investigator has discretion to decline where the accusation is by anonymous letter or is unsigned, but it is a choice, not a ban on investigating.
Is Section 122 an absolute bar to investigating anonymous letters?
No. The Supreme Court has held that Section 122 does not absolutely prohibit an investigator from acting on an anonymous accusation letter.
What should an injured person do to avoid this?
Lodge a proper, signed complaint under the regulations, since an unsigned accusation or a mere request for help without a complaint gives the officer grounds to decline.
Related guides on ThaiLawOnline
Cite this section
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Plain citation
Criminal Procedure Code, s. 122 (Thailand) -
Academic citation
Criminal Procedure Code (Thailand), s. 122. ThaiLawOnline, https://www.thailawonline.com/thai-criminal-procedure-code/section-122/ (accessed 11 August 2026). -
Thai citation
ป.วิ.อ. มาตรา 122 -
Permalink
https://www.thailawonline.com/thai-criminal-procedure-code/section-122/ -
Embed on your site
<blockquote cite="https://www.thailawonline.com/thai-criminal-procedure-code/section-122/"><p>An investigating officer may decline to conduct an investigation in the following cases: (1) when the injured person requests assistance but refuses to lodge a complaint in accordance with the regulations; (2) when the injured person files the case himself without having first lodged a…</p><footer>Criminal Procedure Code, s. 122 (Thailand) — <a href="https://www.thailawonline.com/thai-criminal-procedure-code/section-122/">ThaiLawOnline</a></footer></blockquote>
The Thai text is authoritative. The English is an unofficial translation by ThaiLawOnline, free to reuse with attribution.