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Chain of custody of evidence in Spanish criminal proceedings
Quick answerThe chain of custody is the sequence of collection, identification, transfer, storage and analysis that guarantees that the sample examined by the expert is exactly the one seized from the defendant. A break does not of itself render the evidence unlawful; it undermines its reliability, so the consequence is not nullity under article 11.1 of the Judiciary Organic Act but a loss of evidential weight.
Also cited as: chain of custody · break in the chain of custody · cadena de custodia · identity of the sample · traceability of evidence.
Spanish law contains no unified regulation of the chain of custody. Its basis is drawn from scattered provisions of the Criminal Procedure Act on the collection and preservation of the corpus delicti, supplemented by administrative protocols of the health authorities and forensic police. Case law has settled its nature clearly: it is not an autonomous formal requirement but the instrument that establishes identity between what was seized and what was analysed. The defence must therefore direct its challenge to reliability rather than lawfulness, a frequent error that leads to the ground being dismissed.
Legal framework
Article 282 of the Criminal Procedure Act: the Judicial Police shall investigate public offences committed in their territory, carry out the steps necessary to verify them and identify the offenders, and collect all effects, instruments or evidence of the offence at risk of disappearing, placing them at the disposal of the judicial authority.
Article 326 of the Criminal Procedure Act: where the offence prosecuted has left traces or material evidence of its commission, the investigating judge shall order that these be collected and preserved for the trial if possible, carrying out for that purpose an inspection of the scene and a description of everything that may bear on the existence and nature of the act.
Article 338 of the Criminal Procedure Act: the instruments, weapons and effects referred to in article 334 shall be sealed, and their retention, preservation or dispatch to the appropriate body for storage shall be ordered.
Statutory texts cited from the consolidated versions published by the Spanish Official State Gazette. Unofficial English rendering; the Spanish text is the authentic one.
Key rule. A break in the chain of custody does not give rise to nullity but to an assessment of reliability. The challenge must be specific, reasoned and raised in the written defence in order to compel the attendance of the officers and experts involved.
Key facts
| Nature | Guarantee of identity between what was seized and what was analysed, not an autonomous formal requirement |
|---|---|
| Legal basis | Scattered provisions of articles 282, 326, 334 and 338 of the Criminal Procedure Act and administrative protocols |
| Effect of a break | Loss of reliability and evidential weight, not unlawfulness under article 11.1 of the Judiciary Organic Act |
| Burden of raising it | On the party invoking it, specifying the particular defect |
| Time to challenge | Written defence, with a request for the attendance of those involved |
| Usual field | Narcotic substances, biological samples, electronic devices and weapons |
| Counter-analysis | Contradictory analysis on the reserved sample, where one exists |
Elements and scope
- Collection of the item with a documentary record of the place, time and persons involved, and with sealing preventing manipulation, under articles 326 and 338 of the Criminal Procedure Act.
- Individual identification by numbering or labelling allowing the sample to be traced from seizure to the expert report.
- Documented transfer and storage, stating who received the item, on what date and in what conditions of preservation, a point of particular importance for biological samples and substances liable to degrade.
- Correspondence between the weight, the number of packages and the characteristics described in the seizure record and those recorded in the laboratory report.
- A record of the person carrying out the analysis and of the methodology applied, with a sufficient sample reserved for any counter-analysis.
Points of application
Reliability, not lawfulness. The Second Chamber of the Supreme Court has consistently held that an irregularity in custody infringes no fundamental right and therefore does not trigger the exclusionary rule of article 11.1 of the Judiciary Organic Act. What is compromised is the credibility of the result, a matter of evidential assessment.
Burden of a specific plea. A general invocation of a break is not enough. The defective link must be identified and it must be explained why that defect raises a reasonable doubt as to the identity of the sample.
Timeliness of the challenge. A late challenge, raised in closing submissions or on appeal, is usually rejected because it deprived the prosecution of the opportunity to establish regularity through the attendance of the officers.
Discrepancies in weight and number. Differences between the seizure record and the expert report are the most productive ground, although case law accepts explanations relating to humidity, packaging and weighing method.
Electronic evidence. For device imaging, the guarantee is provided by a hash value and cloning with a write blocker. The absence of a recorded hash is the commonest defect and the hardest to cure.
Defence strategy
Request the complete custody file. The seizure record, the storage register, the dispatch note to the laboratory and the full expert report, not merely its conclusions, should be sought.
Challenge in the written defence. A reasoned challenge compels the attendance of the officers involved and of the expert, and deprives the report of its status as documentary evidence in abbreviated proceedings.
Compare weight, number and description. The contrast between the record and the report is the core of the challenge. It is best set out as a comparative table in the written submission.
Verify the reserved sample. If no sufficient sample was preserved for counter-analysis, expert contradiction has been prevented, which strengthens the doubt as to reliability.
For digital evidence, demand the hash value. The absence of a hash at the time of cloning makes it impossible to establish that the copy analysed matches the original, and should be expressly pleaded.
Are you under investigation or facing charges in Spain? Société Juridique acts for foreign nationals throughout Spain, with offices in Alicante and Madrid and a 24-hour custody line. +34 669 30 21 13 or enquire online.
- Spanish Criminal Code by article
- Criminal Procedure Act by article
- Practical defence guides
- Contact the firm
This page is provided for information only and does not constitute legal advice. The application of any provision depends on the circumstances of the case and requires review of the file by a lawyer. The English rendering of the legal text is unofficial.
Last reviewed: 21 September 2026.
Frequently asked questions
Is the evidence excluded if the chain of custody is broken?
Not automatically. Case law treats the irregularity as affecting reliability rather than lawfulness, so the exclusionary rule of article 11.1 of the Judiciary Organic Act does not apply; the result simply carries less weight.
Which defects matter most?
Discrepancies in weight, number of packages or description between the seizure record and the laboratory report, the absence of sealing and, in digital evidence, the lack of a recorded hash value.
When should I challenge?
In the written defence. A reasoned and timely challenge compels the officers and the expert to attend; a late one is usually rejected.
Is it enough to say the chain was broken?
No. The specific defective link must be identified and it must be explained why it raises a reasonable doubt as to the identity between what was seized and what was analysed.
Can I request a counter-analysis?
Yes, provided a sufficient sample was reserved. If none was preserved, it may be argued that expert contradiction has been prevented.
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