In brief

An error in gathering evidence does not automatically make the evidence unusable. Courts weigh the circumstances. And whoever fails to object in time often loses the point altogether.

Only a few cases are regulated expressly. The most important is Section 136a(3) StPO: statements obtained through ill-treatment, deception, threats or other prohibited methods may not be used, not even with the accused’s consent. Other statutory prohibitions appear, for example, in Section 252 StPO for earlier statements by witnesses who later refuse to testify, and in Section 100d StPO for the core area of private life during surveillance.

Beyond that, the Federal Court of Justice applies a balancing test: the seriousness of the breach is weighed against the interest in clearing up the offence. Deliberate or arbitrary breaches by investigators weigh heavily; errors in borderline cases often do not. Exclusion is accordingly more likely where fundamental rights are concerned than with procedural formalities.

Typical cases

Failure to caution about the right to remain silent before questioning generally makes the statement unusable. The same applies where someone was in fact treated as a suspect but questioned as a witness. A search without a judicial warrant, where investigators merely claimed imminent danger as a pretext, can also lead to exclusion. For blood samples without a judge’s order, the issue has largely disappeared for traffic offences since Section 81a StPO was amended in 2017.

The objection requirement

For many exclusion rules, the Federal Court of Justice requires the defence to object to the use of the evidence at trial by the point referred to in Section 257 StPO, that is directly after the evidence in question has been taken. Remaining silent forfeits the point, including for a later appeal on points of law. We therefore check for possible exclusion from the first access to the file onward and prepare objections in writing.

General explanation, not advice on an individual case. As of November 2026.