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National Expertise Agency

External experts are important in police investigations. The Dutch National Expertise Agency (Landelijke Deskundigheidsmakelaar, ‘LDM’) advises and mediates in the deployment of external experts. This factsheet provides information about how the police use these experts, how one can register as an expert and how you can find the right expertise for your investigative questions.

Why external experts in police investigations?

In criminal investigations, the police sometimes require specialist expertise. External experts can contribute to the investigation because they have expertise that is not available within the police force. For example knowledge of a specific language, culture and religion. Or specific expertise in a certain medical area.

What does the LDM do?

It can be difficult to pinpoint which expertise is needed to answer the specific questions arising during an investigation. The LDM helps to formulate the question and to find the most suitable reliable external expert.
The LDM supports not only the police, but also the judiciary, the Royal Netherlands Marechaussee (Koninklijke Nederlandse Marechaussee) and the Special Investigation Services (Bijzondere opsporingsdiensten, ‘BOD’).

Available areas of expertise

Click here for the areas of expertise registered with the LDM.

Register as an expert

If you are looking to be registered as an expert, please fill in the registration form.

Assessment and screening

An independent Board of Assessment and Advice (College van toetsing en advies, ‘CTA’) decides on the admission of experts. The CTA includes representatives from the judiciary, science, the legal profession and the police force. If you receive a positive evaluation from the CTA, you will be placed on the LDM list for a five year term. After five years there will be a re-assessment. A screening, the reliability and suitability investigation is also part of the procedure and will take place every two years.

CTA Members

  • Mr. J. Grijns, chairman CTA
  • Prof. dr. H. Otgaar
  • Drs. E.A. Langeveld
  • Mr. L.T. Wemes
  • Mr. I.E. Leenhouwers
  • Prof. dr. M.P. Zeegers
  • Mr. W.T. van Mulligen

Assessment model

In order to conduct a substantive assessment of a candidate expert, the CTA makes use of an assessment model. This model is made up of seven parts, namely:

  • specialism
  • own experience and motivation
  • police experience
  • methodology
  • formal registration and training
  • peer appreciation


Experts who perform work via the LDM may receive compensation from the commissioning party. For any questions on this matter, please check ‘Contact’ for further contact information.

Tools for experts

If you have not yet acted as an expert for the police in the investigation phase or for the judiciary in the prosecution phase, you may consult the following links, which may be helpful in this regard. These instruments have been developed in cooperation with the Netherlands Register of Court Experts (Nederlands Register Gerechtelijk Deskundigen, ‘NRGD’). The links refer to web pages of the NRGD.

Tools for applicants or commissioning parties

If you need specific expertise to answer your investigative questions, please contact LDM’s expert advisers. We will help you find high-quality and reliable experts. If you seek expertise on behalf of the judiciary, please see the assessment model: this model is used by the CTA and is comparable to the NRGD's Appointment Questionnaire.


The LDM team can be contacted 24/7 via telephone number +31 (0)88 662 23 36 and by e-mail: ldm@politie.nl.


More about the LDM