The investigative questions in Dutch criminal law are the fixed set of questions a criminal court must answer, in a prescribed order, before it can convict or acquit. Four formal questions follow from Article 348 of the Code of Criminal Procedure (Sv) and four substantive questions from Article 350 Sv. If a formal question is answered against the prosecution, the case ends there and the court never reaches the evidence.
That order is not a formality. It decides where a defence argument has to be made, what the court must respond to in its judgment, and which investigative requests are worth making. This article sets out both sets of questions, and then explains how the defence, the Public Prosecution Service and the victim can influence the answers through investigative requests, known in Dutch as onderzoekswensen.
The four formal questions of Article 348 Sv
Before the merits are reached, the court examines whether the proceedings are validly brought. It asks whether the summons is valid, which turns on whether the charge and the time and place of the alleged offence are stated clearly enough for a defence to be prepared. It asks whether it has jurisdiction over the offence charged. It asks whether the Public Prosecution Service is admissible, which is where limitation, a prosecution brought in breach of the principles of proper procedure, or an earlier decision not to prosecute are raised. And it asks whether there are grounds to suspend the prosecution, for instance where the defendant is not fit to stand trial.
A negative answer to any of these ends the case without a ruling on guilt: the summons is declared void, the court declares itself without jurisdiction, the prosecution is declared inadmissible, or the prosecution is suspended. These are not technicalities to be dealt with in passing. They are the only points on which a case can be stopped before the evidence is weighed.
The four substantive questions of Article 350 Sv
If the formal questions are cleared, the court moves to the merits. It asks whether it is proven that the defendant committed the act as charged, which under Articles 338 and 339 Sv requires lawful means of evidence and the conviction of the court. It asks whether the proven act constitutes a criminal offence, the question of qualification. It asks whether the defendant is criminally liable, which is where grounds of justification such as self-defence and grounds of excuse such as psychological duress are assessed. And it asks which sentence or measure should follow.
The distinction between the second and third questions is often decisive in practice. A justification means the act was not unlawful; an excuse means the act was unlawful but the defendant cannot be blamed for it. Both lead to an acquittal from prosecution rather than a conviction, but they rest on different facts and therefore on different evidence.
Why the order matters
The court must work through the questions in sequence and must give reasons for its answers. Where the defence has advanced a properly substantiated argument on one of the questions, the judgment has to deal with it. A judgment that passes over such an argument, or that answers a later question before an earlier one has been settled, is open to challenge on appeal and in cassation.
One point of statutory housekeeping. The new Code of Criminal Procedure was adopted by the Senate on 24 February 2026 and published in the Bulletin of Acts and Decrees on 13 March 2026, but it enters into force book by book by royal decree. Until that happens the present numbering applies, so Articles 348 and 350 Sv remain the provisions to cite. What the reform will not change is the model itself: a court will still have to work through formal questions before substantive ones.
How the defence steers the investigation
The file that reaches the court is assembled by the police under the direction of the Public Prosecution Service. A defence that waits for the hearing to test that file is usually too late, because by then the witnesses have been interviewed once and the forensic material has been examined once. The statutory route runs the other way: the defence identifies which of the questions of Article 348 or 350 Sv is contestable, and then asks for the investigation that could change the answer.
Article 182 Sv allows the suspect to ask the examining magistrate (rechter-commissaris) to carry out investigative acts during the pre-trial phase. Articles 150a and 150b Sv govern the position of the suspect where an expert examination is ordered and the request for a counter-examination. Under Article 263 Sv the suspect may have witnesses and experts summoned for the hearing, by notifying the public prosecutor at least ten days before it. During the hearing itself a request for further investigation runs through Article 328 Sv, and on appeal new witnesses and experts may be produced under Article 414 Sv.
What makes a request succeed is the reasoning behind it, not the volume of it. A request has to say which question of Article 348 or 350 Sv it bears on and why the requested step could realistically change the answer. In its judgment of 18 November 2025 (ECLI:NL:HR:2025:1711) the Supreme Court set that out for a request to hear an expert whose report incriminated the defendant: the defence must indicate which parts of the report it disputes and why hearing the expert is preferable to another way of testing it. Where a report carries real weight in the proof, the court must also consider whether the proceedings as a whole remain fair if the request is refused.
The same logic applies to technical evidence. In a case before the Rotterdam District Court on 14 August 2019 (ECLI:NL:RBROT:2019:7166) concerning a serious traffic accident under Articles 5 and 6 of the Road Traffic Act 1994, the point at issue was whether the defence could have an independent expert examine the visibility conditions, including the weather and obstructions from the vehicle, in order to test the assessment of culpability. Causation and culpability in traffic cases are often decided on exactly that kind of material.
When a request may be refused
The public prosecutor may decline to summon a witness, in short, where it can reasonably be assumed that the defence is not prejudiced by the refusal, or where the health of the witness would be endangered by giving evidence. That decision is not the last word. A refusal must be given in writing and with reasons, and the request can be renewed before the trial court, which applies its own standard depending on how far the proceedings have advanced.
The role of the Public Prosecution Service
The Public Prosecution Service directs the investigation. It decides which leads the police pursue, it may apply to the examining magistrate for investigative acts under Article 181 Sv, and it summons the witnesses and experts it considers necessary. That position gives it the first say on the content of the file, but not the only say. Prosecutors are also required to establish the truth, which includes securing material that points away from the suspect, and a file that only contains what supports the charge is itself a ground for a request.
Where the prosecution and the defence want different things, the decision falls to the examining magistrate in the pre-trial phase and to the trial court afterwards. The test is the same in substance: whether the requested investigation is necessary or reasonably relevant to one of the questions the court must answer, and whether refusing it would leave the defendant without a fair trial. That is why framing a request in terms of Article 348 or 350 Sv is more effective than framing it in terms of what the defence would like to know.
The position of the victim
The victim in Dutch criminal proceedings is a participant with defined rights, not a party in the way the defence and the prosecution are. Article 51b Sv allows the victim to ask the public prosecutor to add documents to the case file that are relevant to the victim, and to obtain copies of documents from it. A refusal must be given in writing, and the victim can lodge an objection with the examining magistrate within fourteen days. The prosecutor may refuse where the documents are not relevant to the interests of the victim, or where the interests of the investigation or the privacy of others outweigh the request.
The right to speak under Article 51e Sv is aimed at the impact of the offence rather than at the evidence. It can nonetheless affect the investigation indirectly: where a victim states facts at the hearing that do not match the file, the court may order further investigation of its own motion. What the victim cannot do is compel an investigative step in the way the defence can. For a wider picture of how the hearing is structured, see our article on the criminal court hearing in the Netherlands.
What this means if you are facing a charge
Read the charge against the questions rather than against the story. Identify which of the eight questions is genuinely contestable on the file as it stands, and be honest about which are not. Then work out what would have to be established for the answer to change, and ask for that specific step within the applicable time limit. Requests made late, or made in general terms, are refused far more often than requests that are narrow and reasoned.
Timing is the part most often underestimated. The pre-trial phase before the examining magistrate is where witnesses can still be heard properly and where counter-expertise can still be arranged without delaying the trial. Once the case is listed, the threshold for the same request rises. Advice at the stage of the first police interview, before positions are recorded, is therefore usually worth more than advice a month before the hearing; our article on when you need a criminal defence lawyer sets out that timing in more detail.
How we can help
Our criminal lawyers assess the file against the questions of Articles 348 and 350 Sv, formulate and substantiate investigative requests, challenge refusals before the examining magistrate and the trial court, and act for victims who want relevant documents added to the file. We work for suspects and for victims in Eindhoven and Amsterdam, in Dutch and in English. Please feel free to contact us to discuss your case.
Frequently asked questions
What are the substantive questions the judge must answer in every criminal case?
Based on Article 350 Sv, the judge must answer the following questions in strict order: Is it proven that the defendant committed the act as charged?; Does the proven act constitute a criminal offence (punishability of the fact)?; Is the defendant criminally liable for the act (punishability of the offender)?; and what sentence or measure should be imposed. Before reaching these, the judge answers the formal questions of Article 348 Sv: the validity of the summons, the jurisdiction of the court, the admissibility of the prosecution and any ground for suspension.
Which investigative requests (onderzoekswensen) can the defence submit and when?
The defence can request the hearing of witnesses, the appointment of experts, or the addition of documents to the file. These requests can be made during the preliminary investigation, to the examining magistrate under Article 182 Sv; before the hearing, by notifying the public prosecutor under Article 263 Sv; at the hearing itself under Article 328 Sv; and on appeal under Article 414 Sv. Time limits apply, normally ten days before the hearing for witnesses, and every request must state which question it bears on and why.
Can the defence force an expert investigation, or can the prosecution refuse?
The defence cannot strictly “force” an investigation, but they have strong rights. The OM can refuse a request if they deem it irrelevant, unnecessary, or harmful to the investigation (Article 264 Sv). However, the defence can renew the request before the trial court, or ask the examining magistrate to carry out investigative acts under Article 182 Sv; Articles 150a and 150b Sv govern the position of the suspect where an expert examination is ordered and the request for a counter-examination. If the judge deems the expert necessary for the defence’s right to a fair trial, the request must be granted.
How can a victim add documents to the criminal file if the prosecution refuses?
If the Public Prosecutor refuses to add documents relevant to the victim, the victim can use Article 51b Sv. A refusal must be given in writing, and the victim can lodge an objection with the examining magistrate within fourteen days. The examining magistrate then decides.
What role does the right to speak (spreekrecht) play in investigative requests?
The right to speak (Article 51e Sv) is primarily meant for the victim to express the impact of the crime. However, if the victim reveals new facts or contradictions during their statement, this can prompt the court or OM to order further investigation ex officio to clarify the truth. It serves as an indirect method of influencing the scope of the investigation.
When do investigative requests lead to acquittal or a lower sentence?
Requests often lead to acquittal when they successfully challenge the reliability of key evidence (e.g., questioning a breathalyzer’s calibration) or substantiate an alternative scenario (e.g., witness testimony confirming an alibi). A lower sentence often follows where a report obtained at the request of the defence, such as a psychological or psychiatric examination, shows diminished responsibility or personal circumstances that carry weight in sentencing.
How does the examining magistrate assess a request for additional investigation?
The examining magistrate weighs whether the requested investigation is relevant to a question the court must answer and whether it serves the establishment of the truth, against the interests that argue the other way, such as the privacy of others, the progress of the investigation and the burden on witnesses.
Which investigative requests work in traffic cases involving injury or death?
Successful requests usually go to causation and culpability. Common examples are a reconstruction by the traffic accident analysis unit to test speeds, a counter-examination of the visibility conditions at the scene, and a medical report on whether an injury was caused by the collision or by a pre-existing condition.
Can the prosecution formulate investigative requests, and how does that relate to the defence?
Yes, the OM leads the investigation and can independently order investigative acts (Article 181 Sv) or summon experts (Article 260 Sv). The OM essentially builds the initial file. The defence’s requests usually function as a check or balance against the OM’s selection of evidence, ensuring that exculpatory evidence is not overlooked.
What happens if the wishes of the prosecution and the defence conflict?
If the OM wants to proceed to trial but the defence demands further investigation (e.g., interviewing a witness abroad), a conflict arises. The OM may initially refuse the request. Ultimately, the trial judge (or the Examining Magistrate during the preliminary phase) decides. The judge must ensure the defendant has a fair trial. If the judge believes the defence’s request is essential for answering the investigative questions of Article 350 Sv, the judge will overrule the OM and order the investigation.
What are the “investigative questions” (onderzoeksvragen) in Dutch criminal law?
They are a specific legal framework that dictates what a judge must decide in a criminal trial and in what order, forming the backbone of the Dutch criminal justice system under Articles 348 and 350 of the Code of Criminal Procedure.
What formal questions does a judge check first?
Before reaching the merits of a case, the judge checks formal questions such as whether the court has jurisdiction, whether the Public Prosecutor is admissible, whether the statute of limitations has expired, whether the decision to prosecute violated due process, and whether there are grounds for suspension, for example if the defendant is not mentally fit to stand trial.
What substantive questions does the judge answer under Article 350 of the Code of criminal Procedure?
Once the formal hurdles are cleared, the judge addresses four key questions: whether the offence is proven based on legal evidence, whether the proven conduct is actually punishable under the law, whether the defendant personally is punishable given any grounds for excuse or justification, and what sanction should follow.
Why does this framework matter for someone facing a criminal charge?
Understanding the investigative questions is useful for defendants, prosecutors and victims alike, since the answers to these questions determine the direction and outcome of the case at each stage.
