Related Rule
Switzerland
Practice Relating to Rule 100. Fair Trial Guarantees
Section G. Examination of witnesses
Switzerland’s Criminal Procedure Code (2007), as amended to 2012, which regulates the prosecution and adjudication by the federal and cantonal criminal justice authorities of offences under federal law, including war crimes, states: “Parties have the right to be present when the public prosecutor and the courts are taking evidence and to put questions to persons who have been questioned.” 
Switzerland, Criminal Procedure Code, 2007, as amended to 2012, Article 147(1).
In 2007, in its third periodic report to the Human Rights Committee, Switzerland stated:
234. The right to question a prosecution witness is absolute if his or her testimony is decisive from the standpoint of proof. The Federal Court found that this right had been infringed in a case in which there had been no cross-examination during the preliminary proceedings before the examining magistrate and in which the victim had refused, more than four years after the initial hearing, to reply to supplementary questions put by the defendant.
235. The Federal Court clarified this practice one year later. The formal criterion of the importance of the evidence obtained, whether decisive or not, could not determine the admissibility of recourse to anonymous witnesses. Instead the court must consider, as part of an overall assessment, whether the reduction of the rights of defence entailed by acceptance of anonymous witnesses serves interests meriting protection and, if so, whether the accused was nevertheless able to defend himself effectively and had therefore enjoyed due process. In the case before it the Court considered that the rights of defence had been insufficiently safeguarded, for neither the accused nor his counsel had had an opportunity to cross-examine, at least indirectly, one of the two prosecution witnesses. 
Switzerland, Third periodic report to the Human Rights Committee, 17 December 2007, UN Doc. CCPR/C/CHE/3, submitted 12 October 2007, §§ 234–235.
[footnotes omitted]
In 2010, in its Report on IHL and Current Armed Conflicts, Switzerland’s Federal Council stated:
3.4 [Increasing use] of anti-guerrilla tactics
Apart from the direct fight against insurgents, international humanitarian law also addresses other anti-guerrilla tactics. … If members of militias or opposition groups fall into the hands of the government they benefit from the protection of art. 75 of [the 1977] Additional Protocol I as well as that of art. 3 common to the [1949] Geneva Conventions. 
Switzerland, Federal Council, Report on IHL and Current Armed Conflicts, 17 September 2010, Section 3.4, p. 15.
[footnotes in original omitted]