The programme for lay witnesses and expert witnesses in criminal trials is established by the Organic Law 19/1994, of 23 December (B.O.E. 307, 24 December 1994).

The preamble of the Organic Law 19/1994, on the protection of witnesses and expert witnesses in criminal trials, declares that “ daily experience shows that in some cases the citizens may resist collaborating with the criminal police and with the administration of justice in certain criminal trials because of fear of reprisals.

This frequently means that valuable testimony and evidence cannot be relied on in these trials.

Faced with this situation, the legislator must issue regulations that result effective in the defence of those who, like lay witnesses and expert witnesses, must satisfy the constitutional obligation to collaborate with the justice system.

If this is not done, it may be the case that potential witnesses or expert witnesses are unforthcoming or inhibited, in a way that is undesirable under the rule of law. In addition the correct application of the legal and criminal system may be prejudiced and in some cases the guilty may be set free.

It's obvious, however, that the guarantees offered to witnesses and expert witnesses are neither absolute nor unlimited . For example they may not violate the principles of the criminal procedures. Hence the guiding objective of the present Law is to allow for the necessary balance between complying with correct procedures supported by full legal guarantees, and on the other hand protecting the fundamental rights inherent to witnesses and expert witnesses, together with their families.”

The Organic Law continues: “The system in place bestows upon the judge or court the duty to assess rationally the degree of risk or danger and, upon due consideration, apply of all or some of the protective legal measures that may be considered necessary in the light of the trial and the constitutionally protected legal interests at stake. The measures taken in this respect may be appealed within the framework of the right to a defence.”

The Organic Law then states in Article 1 that:

“1. The protection measures envisaged in this Law are applicable to anyone who takes part in a criminal trial as a lay witness or expert witness.“

2. For the provisions of the present law to be applicable, the legal authority must have reasonable grounds for considering that there must be a serious threat to the personal safety or integrity of the person asking for help, or to his or her assets.”

Article 2 states that:

“If the circumstances outlined in the previous Article are deemed to exist, the investigating judge will himself or at the insistence of another party, when necessary in consideration of the degree of risk or danger, agree to the measures needed to conceal the identities of the witnesses and expert witnesses, their domicile, job and place of work, without prejudice to any objections which may be made by defence counsel of the defendant. The judge may adopt the following decisions:

a) That the proceedings will not include the name, surname(s), residence, place of work and occupation, or any other information that could serve as identification. Instead, a number or any other key may be used for this purpose…”

Article 4 states:

“1. Having received this information, the legal authority competent to hold the trial will give a reasoned decision as to whether it will maintain, modify or suppress all or some of the protection measures for the witnesses and experts that were adopted by the investigating magistrate, and if appropriate may adopt other new measures, taking into account the constitutionally protected legal interests, fundamental rights in dispute and the circumstances of the witnesses and expert witnesses in relation to the criminal trial that is being undertaken.

The adopted measures are subject to reform or appeal.

Without prejudice of the above, if either of the parties, the prosecution or defence, enters a reasoned request in their written provisional indictment for the identities of the proposed witnesses or experts to be disclosed, and if their statement or report is considered relevant by the judge or court that is to hear the case, the name and surname(s) of the witnesses and experts must provided, while respecting the remaining guarantees offered to the latter under this Law.

In this case, the deadline for objecting to an expert witness, referred to in Article 662 of the Law on Criminal Proceedings, is calculated from the moment in which the parties are notified of the identities of the expert witnesses.

In the five days following the notification of the identities of the witnesses to the parties, any of the parties may submit new evidence which may prove circumstances that could influence the probative value of their testimonies.

Equally, the parties will be able to make use of the right specified in the above paragraph, in view of the evidence solicited by the other parties and admitted by the court, within the specified time limit for petitions of reform or for an appeal.

The statements or reports of the witnesses and expert witnesses that have been protected under this Law during the preliminary phase of proceedings, may only have the value of evidence, for purposes of the court's final judgment, if they are ratified in the hearing by the person who made the original statement, in the way stipulated in the Law on Criminal Proceedings. If they are deemed impossible to reproduce, under Article 730 of the Law (“The preliminary proceedings may be read at the request of any of the parties when, for reasons unconnected with the parties, they cannot be reproduced in hearing”), they will have to be confirmed by a literal reading in order that they may be subject to rebuttal by both parties.”