Where the seriousness or complexity of the case justifies it, the information may be the subject of a co-investigation in accordance with the procedures laid down in this article.
The president of the judicial court in which there is an investigating division or, if he is prevented from doing so, the magistrate who replaces him shall designate, as soon as the investigation is opened, ex officio or if the public prosecutor so requests in his introductory indictment, one or more investigating judges to be deputies to the investigating judge in charge of the investigation.
At any time during the proceedings, the president of the judicial court may appoint one or more co-investigating judges either at the request of the investigating judge or, if that judge agrees, ex officio or at the request of the public prosecutor or at the request of the parties lodged in accordance with the provisions of the penultimate paragraph of Article 81. The parties may not renew their request for six months. Within one month of receiving the request, the President appoints one or more investigating judges to assist the judge in charge of the investigation. For the application of this paragraph, when the investigation has been opened in a court where there is no investigating division, the president of the judicial court where the territorially competent division is located shall designate the investigating judge in charge of the investigation as well as the co-investigating judge or judges, after the investigating judge initially seised has relinquished jurisdiction in favour of the division; this relinquishment of jurisdiction shall take effect on the date on which the judges of the division are designated.
Where it is not ordered in the manner provided for in the preceding paragraph, in the absence of the agreement of the judge in charge of the information or, failing this, of an appointment by the president of the judicial court within a period of one month, the co-investigating judge may be ordered by the president of the investigating chamber acting ex officio, at the request of the president of the court, at the request of the public prosecutor or at the request of the parties. The presiding judge shall rule within one month of receipt of the request made in accordance with the penultimate paragraph of Article 81 if it is made by a party. Where the investigation has been opened in a court where there is no investigating division, the President of the Examining Magistrate’s Chamber shall refer the matter to the Examining Magistrate’s Chamber for co-investigation. Within one month of the referral, the chamber then decides either, if there are no grounds for co-investigation, to refer the case back to the investigating magistrate, or, if such a decision is essential for the determination of the truth and the proper administration of justice, to relinquish jurisdiction of the investigating magistrate and appoint several investigating magistrates for the purpose of continuing the proceedings.
The decisions of the president of the judicial court, the president of the investigating chamber and the latter provided for by this article are measures of judicial administration not subject to appeal.