Federal Supreme Court, 31.07.2026, 6B_751/2025
Facts
A., a director with individual signatory authority for C. SA, had custody of a 50.66-carat diamond belonging to D., with an estimated value of several million dollars. According to a deposit agreement dated August 16, 2007, with a declared value of USD 20 million, D. was expressly designated as the owner and sole contact person. C. SA could only release the diamond to him or to a person designated through complete written instructions. Despite this obligation, A. handed the diamond over to E.E. The stone has not been located since. Several subsequent documents purported to establish a transfer of ownership or a pledge in favor of E.E., but D. contested their authenticity. On the contrary, he had continued to act as the owner, and A. had confirmed to him as late as 2009 and 2013 that the diamond remained in storage on his behalf. (consid. B.a, 2.2)
The Geneva Police Court found A. guilty of criminal breach of trust and sentenced him to a 15-month suspended prison sentence with a three-year probationary period. The Geneva Court of Justice upheld this judgment. In the meantime, D. had passed away in 2022 in South Africa, and his son, B., had taken over the proceedings as the private claimant. Before the Federal Supreme Court, A. challenged, among other things, this status, his conviction for breach of trust, and the sentencing, citing arbitrariness, the presumption of innocence, a lack of reasoning, and a violation of the principle of speed. (consid. A-C, 1-3)
Law
According toArt. 121 para. 1 CrimPC, when the injured party dies without having waived their procedural rights, these rights pass to their relatives as defined inArt. 110 para. 1 SCC, in the order of succession. However, the procedural status of a private claimant must be distinguished from the substantive ownership of inheritance rights. Regarding criminal matters, each relative belonging to the relevant rank of succession may individually exercise the injured party's procedural rights, even in the presence of other relatives of the same rank. Conversely, for civil claims belonging to an estate, the heirs generally form a necessary joinder and must act jointly. The reference to the "order of succession" in Art. 121 para. 1 CrimPC refers to the abstract order of legal heirs according to Art. 457 SCC and not the actual succession. A foreign element therefore does not mandate the application of foreign succession law to determine the status of a private claimant in criminal proceedings. (consid. 1.1.5, 1.5.1-1.6)
Criminal breach of trust within the meaning ofArt. 138 no. 1 para. 1 SCC requires a movable object belonging to another that has been entrusted to the perpetrator for the purpose of, among other things, safekeeping, administration, or delivery in accordance with received instructions. Appropriation occurs when the perpetrator acts toward the object as if they were the owner and manifests their intent to permanently deprive the true owner of it. Subjectively, the perpetrator must act intentionally and with the aim of unlawful enrichment, which may also include the enrichment of a third party. Regarding the establishment of facts, the Federal Supreme Court reviews the assessment of evidence only under the standard of arbitrariness; purely appellate argumentation is inadmissible. In this context, the principle of in dubio pro reo has no broader scope than the prohibition of arbitrariness. (consid. 1.1.1-1.1.2, 2.1, 2.3.1-2.3.2)
Finally, the sentence is determined based on the offender's culpability in accordance withArt. 47 SCC.Art. 50 SCC requires the judge to state the essential factors that influenced the sanction to allow for its review. The principle of speed, guaranteed by Art. 5 CrimPC and Art. 29 para. 1 Cst., requires that proceedings be conducted within a reasonable time; a violation of this may, in particular, lead to a reduction in the sentence.Art. 52 SCC allows for an exemption only when both the culpability and the consequences of the act are minor. (consid. 3.1.1-3.1.4)
Application to the specific case
B.________ was entitled to act as a private claimant in the criminal proceedings on his own. The notarized affidavit produced made it possible to conclude without arbitrariness that he was the son of D.. The absence of a certificate of inheritance and the potential existence of a spouse or other children had no bearing on his procedural rights. The death of D. in South Africa did not require the application of South African succession law either. Questions relating to the estate, a potential codicil, or escheat concerned civil claims; however, B.________ had specifically been referred to civil proceedings. (consid. 1.5.1-1.6)
Regarding criminal breach of trust, the cantonal court was able to conclude without arbitrariness that D.________ had remained the owner of the diamond. The contract of August 16, 2007, expressly stated this, and no probative material evidence established a pledge or a valid assignment. The documents invoked to the contrary contained inconsistencies, and certain signatures revealed anomalies. Above all, A.________ had himself confirmed to D.________ that the diamond remained deposited on his behalf. By nevertheless handing the stone over to E.E.________ without authorization and without the possibility or intention of returning it, A.________ had misappropriated entrusted property belonging to another. The fact that he derived no personal benefit was irrelevant, as the unlawful enrichment could have benefited E.E.________. The conviction for criminal breach of trust was therefore in accordance with federal law. (consid. 2.2-2.4)
Regarding the sentence, a new violation of the principle of speed did not result from the 13 months that elapsed between the first-instance judgment and the appeal ruling, given the complexity of the case in particular. On the other hand, a previous violation had already been acknowledged due to several periods of procedural inactivity. However, the cantonal court had not indicated to what extent this violation had concretely mitigated the sentence. The same applied to the mitigating circumstance underArt. 48 let. e SCCThis insufficient reasoning prevented the Federal Supreme Court from reviewing the correct application of federal law. An exemption from punishment under Art. 52 of the Swiss Criminal Code was nevertheless ruled out given the appellant's significant culpability and the very high value of the diamond. (consid. 3.2, 3.4.1-3.5)
Outcome
The appeal is partially granted. The status of B.________ as a private claimant and the conviction of A.________ for breach of trust are upheld. However, the cantonal judgment is set aside due to insufficient reasoning regarding the concrete impact of the principle of speed and mitigating circumstances on the sentence, and the case is remanded to the Geneva Court of Justice for a new decision on this point. For the remainder, the appeal is dismissed to the extent that it is admissible. A portion of the court costs, set at CHF 2,000, is charged to the appellant, while the Republic and Canton of Geneva must pay him CHF 1,000 in legal fees. (consid. 3.4.2, 4-5; disp. 1-3)