Expert Witness Disclosure and the Authority of a Single Judge in Criminal Proceedings
Expert Witness Disclosure and the Authority of a Single Judge in Criminal Proceedings
Legal Analysis
1) Nature of a “Special Expert” and Whether Advance Disclosure Is Required
A special expert is a species of witness possessing specialized knowledge, skill, science, art, or technical expertise, called to assist the court in understanding matters that lie beyond ordinary common experience. In criminal proceedings, such a person is treated as an expert witness rather than an ordinary fact witness.
Where the public prosecutor calls a special expert as a witness merely to provide explanation, clarification, or technical assistance to the court, the prosecution is not required to submit the expert’s opinion or report to the accused three days in advance of the testimony.
The reason is that the advance disclosure requirement under Section 243 of the Thai Criminal Procedure Code, particularly paragraph 2, applies only in a case where the court itself orders the special expert to conduct an examination, inquiry, or analysis and to prepare a written opinion or report for the court. If the expert is simply called by a party to testify in court, and is not acting under a prior court order to prepare such written findings, that situation does not fall within the scope of the statutory requirement for prior delivery of the report.
Accordingly, when the prosecution relies on a special expert solely as a witness in open court, no prior three-day notice of the written opinion is necessary, because this is not a case of a court-appointed expert report under Section 243, paragraph 2.
This principle is supported by the Supreme Court precedents referred to in the problem, including Supreme Court Decisions Nos. 588/2499 and 444/2510.
Conclusion:
A special expert is an expert witness. If the prosecutor calls such expert only to testify and explain matters before the court, there is no duty to furnish the accused with the expert’s written opinion three days in advance, because the provision in Section 243 paragraph 2 applies only where the court has ordered the expert to prepare a formal written opinion or report.
2) Whether the Judgment of a Single Provincial Court Judge Is Lawful
In the second problem, a single judge of the Provincial Court sat alone and tried a case involving forgery and assault causing bodily harm, each offense carrying a statutory penalty that, considered separately, fell within the jurisdictional limit for trial by a single judge. At the end of the trial, the judge convicted the accused on both counts, imposed imprisonment, and further ordered detention for a specified period on the ground that the accused was a habitual offender.
The judgment is lawful in both respects.
First, in determining whether a case may be tried by one judge sitting alone under the law governing the organization of the courts, the court must consider the maximum statutory punishment for each count separately, not the aggregate punishment of all counts combined. Therefore, if each individual offense independently falls within the category triable by a single judge, the fact that the accused is ultimately convicted on multiple counts and receives a combined sentence exceeding the limit for one count does not invalidate the judge’s authority to hear and decide the case alone.
In other words, jurisdiction is determined count by count, not by adding together the possible or actual punishment for all charges as a whole. For that reason, the single judge had lawful authority to conduct the trial and render judgment in this case.
Second, the order of detention is also lawful. Under Thai criminal law, detention of this kind is not regarded as a punishment in the strict sense, but rather as a security measure imposed upon certain categories of offenders, such as habitual offenders, in accordance with statutory requirements. Since it is not a criminal punishment in the ordinary sense, the power to order such detention is not excluded merely because the case was tried by a single judge.
Thus, once the single judge had lawful jurisdiction over the offenses, the judge also had authority to order detention as a security measure where the legal conditions were satisfied.
This reasoning accords with the authorities cited in the problem, including Supreme Court Decisions Nos. 530/2480, 1356–1521/2501, and 24/2513.
Conclusion:
The judgment is lawful in both respects:
- the case could validly be tried by a single judge, because jurisdiction is determined by looking at the statutory punishment for each count separately; and
- the order of detention is valid because such detention is not a punishment, but a security measure, which the single judge had power to impose where the law so allowed.