The use of data from the messenger app ANOM — obtained from the USA through mutual legal assistance and introduced as evidence in German criminal proceedings — raises no constitutional concerns in principle. The constitutional complaint was rejected as inadmissible because it failed to set out a violation of fundamental rights with sufficient particularity.
Significance for defense practice
By order of 23 September 2025, the 3rd Chamber of the Second Senate of the BVerfG declined to accept for decision the constitutional complaint of a person sentenced to six years and six months' imprisonment. The complainant had been convicted by the Mannheim Regional Court (Landgericht Mannheim) of drug trafficking in a not-insignificant quantity in six cases. The conviction rested almost exclusively on chat messages from the messenger app ANOM, which had been transmitted to Germany from the USA via international mutual legal assistance. The Federal Court of Justice (Bundesgerichtshof, BGH) had previously dismissed the appeal on points of law (Revision). With this decision the BVerfG provisionally draws a line under the development of German case law on the admissibility of encrypted-messenger data.
ANOM: developed by the FBI, distributed worldwide
ANOM was a messenger app developed by the FBI and covertly distributed to criminal networks. The software installed on the ANOM devices ensured that, without the user's knowledge, an encrypted copy of every message sent was transmitted to a so-called iBot server. There it was decrypted by the FBI, stored again in encrypted form and forwarded to a transfer server. An EU member state that remains unknown to this day provided the server and forwarded the data to the USA without evaluating it itself. From there the data reached Germany through mutual legal assistance. The case differs from EncroChat and Sky ECC in that here the investigating authority itself operated the communications infrastructure — which raises the question of state-induced entrapment and of the requirement of a statutory basis.
The BVerfG's decision: inadmissible, but with pointers
The BVerfG rejected the constitutional complaint as inadmissible: the complainant had not coherently set out the possibility of a violation of fundamental rights. On the basis of his own submissions, the essential circumstances of the data collection were known, so that the objection that "practically nothing" was known about how the evidence had been obtained contradicted itself. On the merits, the Chamber made clear that the principle of mutual trust applies to evidence obtained through mutual legal assistance — in line with extradition dealings. Compliance with minimum rule-of-law standards in the foreign state can be presumed as long as no contrary facts call this into question. The Chamber nonetheless pointed out that a prohibition on the use of evidence may come into play where the foreign collection of evidence infringes the indispensable protection of fundamental rights under Art. 79(3) GG in conjunction with Art. 1 and Art. 20(3) GG, or where the minimum standards of public international law under Art. 25 GG have not been observed.
Duty to refer to the ECJ: standard made specific
The complainant had also argued that the BGH had violated its duty to refer under Art. 267(3) TFEU. The BVerfG made the standard of review more specific: the duty to refer is handled in an untenable manner where the court of last instance does not even consider a referral despite the question being decisive for the outcome (fundamental disregard), or where, in cases of existing ECJ case law, the outcome-relevant question may not yet have been answered exhaustively and the court exceeds the scope of its assessment in an indefensible way (incompleteness of the case law). In the specific case, the Chamber considered that the BGH had stayed within its scope of assessment.
Significance for the defense
The decision does not close the door entirely. The BVerfG expressly emphasized that "so far" it has no findings that would in principle support a prohibition on the use of evidence — wording that leaves room for future developments. In the legal literature, several approaches to the inadmissibility of ANOM data continue to be discussed: breaches of the core area of private life, state-induced entrapment as "structural unfairness", the impossibility of subsequently reviewing how the evidence was obtained, and circumvention of the requirement of a statutory basis. For the defense this means: the admissibility of ANOM data in an individual case remains open to challenge, provided that concrete facts are put forward that call into question the principle of mutual trust. The BVerfG's high requirements for substantiating the constitutional complaint do, however, serve as a warning to build up the factual submissions on the circumstances of the data collection carefully already at the trial-court stage — including the question whether a referral to the ECJ under Art. 267(3) TFEU should be suggested.