Related Rule
Spain
Practice Relating to Rule 100. Fair Trial Guarantees
Section N. Non bis in idem
Spain’s LOAC Manual (1996) provides: “Prisoners of war cannot be punished more than once for the same act or the same accusation.” 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Publicación OR7-004, 2 Tomos, aprobado por el Estado Mayor del Ejército, División de Operaciones, 18 March 1996, Vol. I, § 8.7.b.
Spain’s LOAC Manual (2007) states: “Prisoners of war may not be punished more than once for the same act or on the same charge.” 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Tomo 1, Publicación OR7–004, (Edición Segunda), Mando de Adiestramiento y Doctrina, Dirección de Doctrina, Orgánica y Materiales, 2 November 2007, § 8.7.b.
Spain’s Law on Judicial Power (1985), as amended in 2009, states:
2. … [Spanish courts] have jurisdiction over acts that constitute offences according to Spanish penal law even if these were committed outside the national territory, as long as those criminally responsible were Spanish nationals or foreigners who had acquired Spanish nationality prior to the commission of the act, and if the following conditions are met:
c. That the offender has not been acquitted, pardoned or sentenced abroad or, in the latter case, has not completed his or her sentence abroad. If he or she only completed it partly, this will be taken into account in order to proportionally reduce the [sentence] which he or she must complete.
4. Spanish courts have jurisdiction over offences committed by Spanish and foreign nationals outside the national territory, which constitute any of the following offences according to Spanish law:
h. Any other [act] that according to international treaties and conventions, in particular those Conventions on international humanitarian law and the protection of human rights, must be prosecuted in Spain.
Without prejudice to that disposed by the treaties and international conventions that Spain is a party to, in order for Spanish tribunals to have jurisdiction over the above-mentioned offences it must be demonstrated … that no other procedure leading to an investigation or effective prosecution, as the case may be, of the same punishable acts has been initiated in another country with jurisdiction or within an international tribunal.
The prosecution initiated before Spanish courts will be temporarily dismissed when it is established that another process on the denounced acts has been initiated in the country or tribunal referred to in the above paragraph.
5. If the prosecution is transferred to Spain according to the conditions in … paragraph 4, paragraph 2(c) of this article will in any case be applicable. 
Spain, Law on Judicial Power, 1985, as amended on 3 November 2009, Article 23(2)(c) and (4)(h) and (5).
In 2009, in the Gaza case, the Criminal Chamber of Spain’s National High Court was called upon to decide the appeal of the Prosecution Service in a case concerning a bombing in Gaza in 2002 by the Israeli Air Force. The Court referred to the facts of the case as falling under “offences against protected persons and objects in the event of armed conflict” in the Penal Code (1995). 
Spain, National High Court, Gaza case, Judgment, 9 June 2009, Fundamentos Jurídicos, Tercero, p. 4.
The Court noted:
B) With regard to the principle of universal justice, established in Article 23(4) of the L.O.P.J. [Law on Judicial Power (1985)], its applicability is not to be considered absolute …
a) In the legal framework, Article 23(5) of the L.O.P.J. establishes a first limitation, as Spanish courts have jurisdiction over offences committed by Spanish and foreign [nationals] outside the national territory, which may constitute acts that, according to international treaties and conventions, must be prosecuted in Spain … However, this is only the case provided that the offender has not been acquitted, pardoned or sentenced abroad or, in the latter case, has not completed his or her sentence or has only completed it partly (Article 23(2)(c) of the L.O.P.J.).
In addition, Article 17 of the [1998] … ICC Statute … offers certain criteria on the admissibility and inadmissibility to hear situations referred to it when certain circumstances are met.
In order to determine the willingness or unwillingness [of a State] to act in a particular case, the Court shall consider, having regard to the principles of due process recognized by international law, whether one or more of the following exist, as applicable: … [t]he proceedings were or are being undertaken. 
Spain, National High Court, Gaza case, Judgment, 9 June 2009, Fundamentos Jurídicos, Tercero, p. 4.
The Court further noted:
b) In jurisprudence, the principle of universal jurisdiction has also been qualified by important nuances.
a) The S.T.C. 237/05 [Constitutional Court judgement] of 26 September 2005 (Guatemala case) and STC 227/07 of 22 October 2007 (Falun Gong case) [judgement] have established the following criteria on the matter:
2.- Concerning the tension between the principle of concurrence and the principle of subsidiary [jurisdiction], it is noted that there are important reasons … that have resulted in the prioritization of the locus delicti, which is part of the body of International Criminal Law. Based on this fact, … it is true that … the principle of subsidiarity should not be seen as a rule opposed to, or diverging from, that which introduces the principle of concurrence as, in view of concurrent jurisdictions and in order to avoid the eventual duplication of processes and the infringement of the principle of ne bis in idem, the introduction of a rule of prioritization is indispensable. 
Spain, National High Court, Gaza case, Judgment, 9 June 2009, Fundamentos Jurídicos, Tercero, pp. 5–6.