The doctor as expert witness (perito) under Law 906 of 2004
- Topic
When the justice system needs medical knowledge, the doctor acts as an expert (perito): examines, reports in writing and explains the opinion at the oral trial.
What it is
Law 906 of 2004 (the Colombian Code of Criminal Procedure) regulates expert evidence in articles 405 to 423. It applies when scientific, technical, artistic or specialised knowledge is needed, and the rules for witnesses apply to the expert where relevant. The service is provided by experts of the judicial police, the National Institute of Legal Medicine and Forensic Sciences (INMLCF), public or private bodies and specialised private individuals. In the adversarial system the written report is not enough: the expert must testify at the oral trial, where the parties examine and cross-examine them. For a public servant, appointment as an expert cannot be refused.
Key facts
- Art. 405: expert evidence applies to assessments that need scientific, technical, artistic or specialised knowledge; the rules for witnesses apply to the expert.
- Art. 406: the service is provided by the judicial police, the INMLCF, public or private bodies and specialised individuals; all give their opinion under oath.
- Art. 408: experts may be people with a legally recognised degree and, in other circumstances, people of recognised knowledge even without a degree.
- Art. 409: the following may not be appointed: people under 18, people suspended from practising their profession while the suspension lasts, and people convicted of a crime who have not been rehabilitated.
- Art. 410: the appointee may decline only for an illness that prevents the work, lack of adequate means or serious harm to their interests; an unjustified refusal is fined.
- Art. 411: the same grounds for disqualification and challenge that apply to the judge apply to experts.
- Art. 420: the judge weighs expert evidence by the expert's technical, scientific and moral fitness, the clarity of the answers, the acceptance of the principles relied on, the instruments used and overall consistency.
Next step: what to do and document
- When a request arrives from an authority (prosecutor, judicial police or judge), check who is asking, what questions they ask and which case it concerns.
- If there is a conflict (kinship or interest in the case, close friendship or serious enmity with a party; Law 906, art. 56), declare it at once and in writing.
- Examine and document methodically: describe before interpreting, and record date, time, place and who was present.
- Answer only the questions asked, within your own competence, and state the limits of the examination.
- Keep a copy of the report and your notes: the summons to the oral trial may come months or years later.
Legal framework in Colombia
- Law 906 of 2004 (Code of Criminal Procedure), arts. 405 to 423: expert evidence.
- Law 906, art. 204: the INMLCF gives technical and scientific support to the prosecution service and the judicial police, and also to the accused or their defence lawyer when they ask.
- Official text checked on 2026-11-05 at funcionpublica.gov.co (Gestor Normativo, Law 906 of 2004).
Test yourself
Think of the answer, then tap the question to see it.
What happens to the expert report if the expert does not testify at the oral trial?
It is not admissible as evidence: Law 906 (art. 415) requires the expert to testify orally at trial.
Can a doctor who is a public servant refuse to act as an expert when appointed?
For a public servant the appointment is mandatory (art. 410). The only excuses are an illness that prevents the work, lack of adequate means or serious harm to their interests.
Can a psychiatric expert state at trial that the accused is not criminally responsible (inimputable)?
No. Art. 421 of Law 906 bars experts from addressing the accused's inimputability; they describe the disorder and its effects, and the judge decides.
Which grounds for disqualification and challenge apply to experts?
The same as for the judge (Law 906, art. 411). If the disqualification or challenge is accepted, the judge excludes the expert.
Connections
Educational content on forensic and legal medicine; not legal advice and no substitute for the technical guides of Colombia's National Institute of Legal Medicine and Forensic Sciences. Laws change: each page links the official text and says when it was last checked. For a real case, follow the guide in force and ask the competent authority.
Sources: Ley 906 de 2004, Código de Procedimiento Penal (Función Pública, Gestor Normativo, 2004).
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