This guide is informational. Always verify how the rules apply to your specific case.
Brief Answer: A preliminary investigation should be initiated when there is reason to believe that a crime subject to public prosecution has been committed, unless a legal exception applies. The police or prosecutor leads the investigation. It should be conducted objectively and as promptly as circumstances allow. When the investigation is complete, a reasonably suspected individual and their defense attorney are normally given final notification, reasonable time to review the material, and the opportunity to request supplementation before the prosecutor decides on prosecution. If the evidence is insufficient or there is no longer reason to continue the investigation, it should be discontinued.
There is no general statutory time limit for how long a Swedish preliminary investigation may last. The duration varies from days to several years depending on the nature of the crime, detentions, technical examinations, international measures, and the scope of the investigation. The requirement in Chapter 23, Section 4 of the Code of Judicial Procedure (RB) is instead that the work should be conducted promptly and that the investigation should be concluded as soon as it can be completed.
This guide describes the process. For your rights during interrogation and detention, read Suspected of a Crime – from Police Interrogation to Detention. For the document itself and public access, read Preliminary Investigation Protocol – Requesting Access, Confidentiality, and Redaction.
The Course of the Preliminary Investigation in Eight Steps
| Step | What Happens? | What Should You Keep Track Of? |
|---|---|---|
| 1. Information about the Crime | The police or prosecutor becomes aware of a possible crime, often through a report but sometimes in other ways. | Report number, date, classification, and which authority is handling it. |
| 2. Initial Decision | The competent decision-maker assesses whether there is reason to believe that a crime subject to public prosecution has been committed. | Whether a preliminary investigation has been initiated or if the report has been dismissed. |
| 3. Investigation Leadership | The police or prosecutor leads the work. The prosecutor takes over in cases where the law requires it. | Who is the investigation leader and who is the case handler. |
| 4. Investigative Measures | Interrogations, technical examinations, collection of documents, seizures, and other permitted measures are carried out. | What information you have provided, what evidence you have pointed to, and any decisions on coercive measures. |
| 5. Suspicion | When someone is heard as reasonably suspected, the person must be informed of the suspicion and their central rights. | Act, time, place, classification, degree of suspicion, and defense attorney. |
| 6. Insight and Final Notification | The suspect receives certain ongoing insight. When the investigation is deemed complete, the suspect and the defense attorney should be allowed to review the material. | What material has been provided, the final response date, and if anything is missing. |
| 7. Supplementation | The suspect can request further interrogations or other measures and provide comments. | Request in writing, concretely, and with an explanation of the measure's significance. |
| 8. Decision | The prosecutor initiates prosecution if the evidence is deemed sufficient. Otherwise, the preliminary investigation may be discontinued or concluded in another legal manner. | Decision date, reasoning, prosecution deadline, and the possibility of review. |
When Should a Preliminary Investigation Be Initiated?
The main rule in Chapter 23, Section 1 of the Code of Judicial Procedure (RB) is that a preliminary investigation should be initiated as soon as there is, due to a report or other reason, reason to believe that a crime subject to public prosecution has been committed. The threshold is low. It is not required that a specific person is already suspected.
A preliminary investigation does not need to be initiated if it is obvious that the crime cannot be investigated. There are also rules regarding, among other things, investigation limitations and simplified processing. Therefore, the filing of a report does not automatically mean that a full preliminary investigation will start.
The purpose is stated in Chapter 23, Section 2 of the RB. The investigation should clarify:
- who can reasonably be suspected of the crime,
- whether there are sufficient grounds for prosecution, and
- the case so that the evidence can be presented collectively at an upcoming main hearing.
A preliminary investigation is thus both a criminal investigation and a preparation for a potential trial. It is not intended to confirm a predetermined theory.
Who leads the preliminary investigation – police or prosecutor?
According to Chapter 23, Section 3 of the Code of Judicial Procedure (RB), the decision to initiate a preliminary investigation is made by the Police Authority, the Security Service, or a prosecutor. The distribution depends on the case's situation and nature.
| Situation | Usual Leadership | Practical Implication |
|---|---|---|
| No one is yet reasonably suspected, and the case is not prosecutor-led for other reasons. | Police Preliminary Investigation Leader | The police plan and prioritize the investigative measures. |
| Someone is reasonably suspected, and the case is not of a simple nature. | Prosecutor | The prosecutor takes over the leadership. The police usually carry out many of the measures. |
| Special reasons make it necessary. | Prosecutor | The prosecutor can take over earlier, for example, due to the nature of the case. |
The investigation leader decides which measures to implement but is bound by law, the principle of objectivity, proportionality, and expediency. A complainant, suspect, or defense attorney can propose measures but cannot direct the investigation themselves.
The principle of objectivity applies to the entire investigation
According to Chapter 23, Section 4 of the RB, the investigation leader and those assisting the investigation must seek, preserve, and consider circumstances and evidence that speak both in favor of and against the suspect. The evidence should not be sorted based on which side it benefits.
Objectivity means, among other things, that alternative scenarios should be tested when they have reasonable support, that clear counter-evidence should not be overlooked, and that exculpatory information should be documented and evaluated. However, the principle does not guarantee that every proposed measure must be carried out. The measure must be relevant, feasible, and proportionate.
The preliminary investigation should also be conducted so that no one is unnecessarily subjected to suspicion, cost, or inconvenience. Coercive measures and other interventions should not be used more extensively than the purpose requires.
How long does a preliminary investigation take?
The RB does not specify a common maximum time for all preliminary investigations. Instead, the expediency requirement in Chapter 23, Section 4 applies: the investigation should be conducted as swiftly as circumstances allow. When there is no longer reason to continue it, it should be closed.
| Factors Affecting Time | Example |
|---|---|
| Case Scope | Number of suspects, complainants, witnesses, crime incidents, and seizures. |
| Technical Analyses | DNA, IT forensics, phone extractions, accounting, and forensic reports. |
| International Measures | Legal assistance, information from platforms or individuals in other countries. |
| Deprivation of Liberty | Arrest, detention, and remand entail special and significantly stricter time limits. |
| Priority Rules | Cases with young suspects or those deprived of liberty should be handled particularly swiftly. |
The fact that a case is old does not in itself prove that the expediency requirement has been violated. The assessment depends on which measures have actually been taken, whether there has been prolonged inactivity, and whether the delay has a justifiable explanation.
How to follow up on a slow case
- Request the case number and who the investigation leader is.
- Ask when the latest investigative measure was taken and what type of measure remains. Confidentiality may prevent details from being disclosed.
- Describe if the delay causes a concrete legal loss, such as evidence at risk of disappearing.
- Request a written statement on the case's status, but do not expect the authority to provide an exact end date.
- In cases of long and unexplained inactivity, a report to the Parliamentary Ombudsman (JO) may be considered. However, the JO usually does not change the actual prosecution or closure decision.
Access during an ongoing preliminary investigation
When the suspect has been informed of reasonable suspicion, the suspect and the defense attorney have the right, according to Chapter 23, Section 18 of the RB, to continuously access what has occurred during the preliminary investigation, to the extent that it can be done without harming the investigation. Access may therefore be limited while, for example, interviews are pending or evidence is at risk of being influenced.
This right is party access in the criminal process. It should not be confused with the public's right to request public documents under the Freedom of the Press Act (TF). An outsider may encounter preliminary investigation confidentiality under the Public Access to Information and Secrecy Act (OSL), while a suspect's access is assessed according to specific procedural rules and may be stronger.
| Suspect and Defense Counsel | Public and Media | |
|---|---|---|
| Legal Basis | Primarily Chapter 23 of the Code of Judicial Procedure (RB) and rules on party access. | Chapter 2 of the Freedom of the Press Act (TF), with limitations in the Public Access to Information and Secrecy Act (OSL). |
| When? | Continuously after notification of reasonable suspicion, but access may be restricted if the investigation is harmed. | When the requested item is a public document; confidentiality is assessed on a case-by-case basis. |
| Purpose | To be able to safeguard the defense and influence the investigation. | Public oversight of government activities; a specific purpose usually does not need to be stated. |
Read more about public access to documents in the guide to requesting government documents.
Final Notification When the Investigation is Considered Complete
When the lead investigator considers the necessary investigation complete, the suspect and defense counsel must be informed according to Chapter 23, Section 18 a of the RB. They must be given the opportunity to review what has transpired and be given reasonable time to indicate what further investigation they believe is needed and otherwise provide comments. Prosecution cannot be decided before this has occurred.
Final notification is not an indication that prosecution will definitely be initiated. It means that the lead investigator assesses that the investigation has reached a stage where the defense should have a final real opportunity to respond before the decision to prosecute.
The length of the response time depends on the scope and complexity of the material. There is no general deadline for all cases. If the time is too short, you or the defense counsel should immediately request an extension and explain why: number of pages, new technical material, need for interpretation, or a specific investigative measure.
Check This at Final Notification
- Is the description of the act and the current legal classification clear?
- Are all interviews and attachments referred to in the material available?
- Are audio, film, photographs, analysis files, or technical protocols accessible?
- Have details that speak in your favor been documented?
- Are there summaries that do not match the source material?
- Have new details emerged so late that you need additional time?
- Is there material not included in the preliminary protocol but still present in the investigation?
How to Request Supplementation of the Preliminary Investigation
The suspect and defense counsel may request further investigation. According to Chapter 23, Section 18 b of the RB, a requested measure should be taken if it is likely to be significant for the preliminary investigation. If the request is denied, the reasons must be stated.
A useful request for supplementation ties the measure to a disputed issue:
To the lead investigator in case [case number] I request that the following supplementary investigative measure be conducted: [specific measure, such as an interview with a named person or retrieval of a specific log] The measure is likely to be significant because: [which statement or sequence of events the measure can confirm or refute] The material should be obtainable from: [place, person, system, or time period] If the request is denied, I request that the reasons be stated in writing. /pre>Examples of possible supplements include a new or in-depth interview, verification of a timeline, retrieval of camera or location data, technical review of a file, or documentation supporting an alternative sequence of events. The more specific the measure, the easier it is to assess its relevance and feasibility.
If the lead investigator denies a request, the suspect may report the matter to the court according to Chapter 23, Section 19 of the RB. The court can hold a hearing and decide on the matter. Discuss the form and timing with the defense counsel, as the review concerns a specific investigative measure and not general dissatisfaction with the investigation.
Discontinuation, Resumption, or Prosecution
According to Chapter 23, Section 4 of the RB, the preliminary investigation should be discontinued when there is no longer reason to pursue it. Common explanations are that it is not possible to prove that a crime has been committed, that a certain person cannot be linked to the act, or that the available evidence is insufficient for prosecution. The exact reason must be stated in the decision.
| Outcome | What Does It Mean? | What Can Happen Later? |
|---|---|---|
| The Preliminary Investigation is Discontinued | The investigation is concluded without prosecution in its current state. | It can be resumed if new circumstances or new evidence provide grounds for it and the crime is not time-barred. |
| No Prosecution is Initiated | The prosecutor assesses that the conditions for prosecution are lacking, often because the evidence does not meet the requirement. | The decision can be requested for review within the prosecution authority. |
| Prosecution is Initiated | The prosecutor files an indictment and presents the act and evidence in court. | The court independently examines the prosecution. Prosecution is not the same as a conviction. |
The decision by the preliminary investigation leader or prosecutor to discontinue an investigation is not an acquittal and does not carry the same legal force as a judgment. Therefore, new relevant information can lead to the reopening of the investigation.
If you are a complainant and wish to challenge a discontinuation decision
First, request the complete written decision and the reasoning behind it. A request for review is normally sent to the prosecutor's office where the decision was made and is reviewed by a higher prosecutor. Point out which specific circumstance was incorrectly assessed or which available investigative measure is missing. Also, read When public prosecution is not initiated – what you can do.
Checklist throughout the preliminary investigation
- Identify the case: save the report number, diary number, and contact information.
- Check the role: complainant, witness, informant, or suspect.
- Request precision: note the act, time, place, classification, and degree of suspicion.
- Document: save summonses, decisions, your own submissions, and dates of contacts.
- Secure evidence early: indicate where transient information such as films, logs, or messages can be found.
- Distinguish source from conclusion: mark what someone actually said and what the investigator summarized.
- Follow status without speculating: ask what can be disclosed and when the latest action was taken.
- At final notification: check the list of materials, attachments, and response time.
- Request specific supplementation: action, evidence theme, source, and significance.
- Request a decision: do not settle for an oral statement if you need to be able to proceed.
Common questions about preliminary investigations
How do I know if a preliminary investigation has been initiated?
Ask the Police Authority or the prosecutor's office with reference to the case number. The authority can often inform about the status, but ongoing investigations and information about individuals may be subject to confidentiality.
Can the police investigate before someone is suspected?
Yes. The preliminary investigation can begin as soon as there is reason to believe that a crime under public prosecution has been committed. A designated person is not required.
Do I have the right to know everything during the investigation?
No. A reasonably suspected person and their defense attorney have ongoing party access, but before the final notification, access may be limited if disclosure would harm the investigation. An outsider is assessed instead according to TF and OSL.
How long is a normal preliminary investigation?
There is no legally established standard time. A simple case can be concluded quickly, while technical or international investigations can take a long time. The decisive legal requirement is prompt handling based on the circumstances.
Can the prosecutor initiate prosecution before final notification?
Not when the rules on final notification are applicable. The suspect and the defense attorney must first be allowed to review the material and have reasonable time to request supplementation and provide comments.
Must the police do everything I request?
No. A requested supplementation should be carried out if it is deemed to be of significance to the preliminary investigation. If denied, the reasons must be stated, and the matter can be reported to the court under the conditions in Chapter 23, Section 19 of the Code of Judicial Procedure.
Does a discontinued preliminary investigation mean the suspect is declared innocent?
No. A decision to discontinue means the investigation is not pursued. It is not a court judgment. At the same time, the presumption of innocence applies: someone who has not been convicted should not be treated as guilty.
Can a discontinued preliminary investigation be reopened?
Yes. If new circumstances or new evidence emerge, the investigation can be reopened, as long as other legal obstacles such as prescription do not exist.
Related guides
- Preliminary investigation protocol – request, confidentiality, and redaction
- Suspected of a crime – rights during police interrogation and detention
- Requesting official documents step by step
- When public prosecution is not initiated
- How does a trial proceed?
Official sources and further reading
The rules on party access in the Code of Judicial Procedure and public access to documents according to TF and OSL should be assessed separately. The applicable legal basis depends on your role and the material you request.
- Code of Judicial Procedure (1942:740), particularly Chapter 23
- Preliminary Investigation Ordinance (1947:948)
- Public Access to Information and Secrecy Act (2009:400), including Chapter 18
- Swedish Police Authority: From Report to Verdict
- Swedish Prosecution Authority: Preliminary Investigation
- Swedish Prosecution Authority: Review
Last reviewed against public statutes and official sources: July 29, 2026. The information is general and does not replace advice from a defense attorney or victim's counsel in an individual case. Legislation, practice, and agency procedures may change.
