Last updated on September 5, 2026
A public prosecutor (พนักงานอัยการ, phanakngan aiyakan, often just aiyakan or state attorney) is an officer of the Office of the Attorney General who conducts criminal prosecutions in the name of the state under the Public Prosecutor Organ and Public Prosecutors Act B.E. 2553 (2010). The prosecutor receives the police investigation file, decides whether to indict, presents the case in court and handles appeals. For a foreigner who has been arrested, the prosecutor’s decision is the point at which a police matter becomes, or does not become, a court case.
Table of Contents
Where the prosecutor sits in a criminal case
The police investigate; the prosecutor decides. Under the Criminal Procedure Code the inquiry official gathers evidence and sends the file, with an opinion, to the public prosecutor. The prosecutor may order further inquiry, issue a prosecution order and file the indictment, or issue a non-prosecution order. A non-prosecution order is reviewed by the police commissioner or provincial governor, and if they disagree the file goes to the Attorney General for a final decision. Once the indictment is filed the prosecutor is the plaintiff, calls the witnesses and argues sentence.
The Office of the Attorney General is an independent organ under the Constitution, separate from the police and the courts. Prosecutors are career officers who hold the Thai Bar qualification and pass a competitive examination, organised into provincial offices and specialised departments, including the one that handles extradition and mutual legal assistance.
What a foreigner should expect
Reporting dates. A suspect released on bail during the inquiry is usually given a date to report to the prosecutor’s office; failing to appear forfeits the bail and can lead to an arrest warrant. Where the suspect is detained, the prosecutor must file the charge within the periods of court-ordered detention, which is why cases against detained foreigners move faster. Each meeting with the prosecutor is an opportunity to submit written evidence and a statement in mitigation, with a lawyer and an interpreter present.
Settlement. In a compoundable offence such as defamation, fraud or simple assault, a settlement with the injured party and withdrawal of the complaint ends the prosecution, even after indictment. A non-compoundable offence cannot be settled away, but a repaid victim and a guilty plea will be reflected in the sentence. Prosecutors also represent the state in civil matters and file public-interest petitions, for example to place an incapacitated person under guardianship.
Public prosecution versus private prosecution
Thailand allows the injured person to prosecute directly. Instead of, or alongside, a police complaint, the victim may file a criminal complaint in court through a licensed lawyer; the court then holds a preliminary hearing to decide whether there is a prima facie case. This route is common in cheque, fraud and defamation cases where the police are slow. The victim may also join a public prosecution as co-plaintiff to claim compensation in the same proceedings.
| Public prosecution | Private prosecution | |
|---|---|---|
| Who files | Public prosecutor | Injured person through a lawyer |
| Screening | Prosecution or non-prosecution order | Preliminary hearing by the court |
| Cost to the victim | None | Lawyer’s fees; no court fee on the criminal claim |
| Control over the case | State; victim may join as co-plaintiff | Victim, who may withdraw a compoundable case |
The prosecutor is neither judge nor police officer: a non-prosecution order is not an acquittal, and an indictment is not a conviction. The trial is for the court.
Frequently asked questions
What does a public prosecutor do in Thailand?
The prosecutor reviews the police inquiry file, decides whether to prosecute, files the indictment and conducts the trial for the state, including appeals. Prosecutors belong to the Office of the Attorney General, an independent body, and also represent the state in civil cases and file public-interest petitions such as guardianship applications.
Can a public prosecutor drop charges in Thailand?
Yes. Before indictment the prosecutor may issue a non-prosecution order, subject to review by the police commissioner or provincial governor and, in case of disagreement, the Attorney General. After indictment, a compoundable offence ends when the victim withdraws the complaint following a settlement; other charges can only be withdrawn with the court’s permission.
Do I have to appear before the prosecutor if I am on bail?
Yes. Reporting to the prosecutor on the date given is a condition of release, and missing the appointment can result in forfeiture of the bail money and an arrest warrant. Bring a lawyer and, if needed, an interpreter, because the meeting is also the moment to hand in evidence or a written statement.
See also: inquiry official, bail, compoundable offence, courts of first instance, and our guides to criminal trial procedures in Thailand and what to do if arrested in Thailand.
Thai Law Updates, free by email
Plain-English updates on Thai law changes that affect foreigners: property, visas, marriage, business and wills. One short email a month from a firm practicing since 2006. No spam, unsubscribe anytime.