To be grounds for detainment, interference must involve violence: breaking away from an arresting officer is considered violence, while passive physical refusal to cooperate is not. Furthermore, attempts of suspects or witnesses to hinder official activities are only considered unacceptable when the police officer is legally acting in the line of duty. Examples show legal and illegal reactions of officers to interference. Locking up a suspect during a search is only permissible as long as the physical act of conducting the search is actually in progress. If the arresting officer makes an arrest because he mistakenly believes that an individual is guilty of an offense, the arrest is legal. However, if an error results because the officer misinterprets a legal point that he should understand, the arrest is unacceptable. An individual can be locked up temporarily for the duration of an interview to halt disruption of questioning conducted by a police officer. Officers may confiscate cameras to prevent future disturbances to their official activities. Film however, may be destroyed only if officers object to pictures taken of them without their permission, as this act interfere with their personal rights. The right to various kinds of self-defense extends to all officers fulfilling their official obligations, including customs and tax officers. Notes are supplied. --in German.