Precautionary Mirroring of Mobile Phone Data Is Permissible

In case 7B_550/2024 (23 January 2026, intended for official publication) from the Canton of Zurich, the Federal Supreme Court permitted the immediate mirroring of mobile phone data upon seizure, even before the sealing procedure has been completed.

Since mobile phones today often automatically delete or encrypt data, the window for securing evidence is becoming technically narrower. Requiring law enforcement to wait out the three-day sealing period risks irreversible data loss.

The Federal Supreme Court justified its decision on the basis that mirroring does not constitute actual reading of the data: it is a purely technical process carried out by a forensic expert and thus not directly by the prosecuting authority. The mirrored storage medium is subsequently sealed, meaning the authority gains no insight into the contents before the unsealing procedure is concluded.

As a safeguard against misuse: the forensic experts who carry out the mirroring may not later be involved in the actual investigative work of the case.

The ruling means that accused persons data can be mirrored directly from the moment of seizure, such that an interference with privacy has already occurred at that point. The decision thus weighs investigative interests as generally more important. Furthermore, it will likely be difficult for accused persons and their defense counsel to verify whether the court-imposed condition was complied with, namely, that the forensic experts carrying out the mirroring must not be involved in the investigative activity in any way.