Criminal law and criminal procedure
Substantive law
Act No. 40/2009 Sb. (trestní zákoník) defines a crime as an unlawful act that is culpable and socially harmful, committed by a person aged 15 or over who is criminally responsible. Fault is intentional (direct or indirect) or negligent (conscious or unconscious). Preparation and attempt are punishable only where the Code says so; voluntary withdrawal (dobrovolné upuštění) removes liability for the attempt. Participants are the perpetrator, co-perpetrator, organizer, instigator and aider.
Defences include self-defence (nutná obrana), necessity, permissible risk and consent. Sanctions range from conditional sentences, community service and fines to imprisonment (up to 20 years, or life for exceptional cases), disqualification and forfeiture; protective measures include detention and treatment.
Procedure
Act No. 141/1961 Sb. (trestní řád) governs the preparatory proceedings, indictment, trial, appeal and execution. The police conduct investigation under the supervision of the public prosecutor; the court decides guilt and sentence. Coercive measures require statutory grounds: police detention (zajištění) may last at most 48 hours, while custody (vazba) requires a court decision and one of the statutory reasons (flight, collusion, repeat offending). House searches and interception require judicial authorisation in principle.
The accused enjoys the presumption of innocence, the right to counsel, the right to an interpreter, nemo tenetur and ne bis in idem. Evidence includes witness testimony, expert opinion, inspection, documents and electronic data. Remedies are complaint (stížnost), appeal (odvolání), retrial (obnova řízení), cassation (dovolání) and a constitutional complaint.
Worked example
Police detain a suspect in a robbery for 40 hours and then seek custody. He has a fixed residence, a job and no record; the only ground alleged is the seriousness of the offence. Seriousness alone does not justify custody. The court should release him and may impose an alternative measure such as bail or electronic monitoring. If the court orders custody without reasoning, the decision is defective.
Traps
Confusing detention with custody and missing the 48-hour limit; ignoring the 8-day appeal period against a judgment; treating all participants as perpetrators; and forgetting that custodial grounds must be specific and reasoned.