While there is a need for sophisticated police technology to investigate burgeoning criminal activities, expecially those of organized crime, certain actions may tend to infringe on individual freedoms. Thus photographs and films are incriminating evidence, but pictures may also misrepresent a situation or be forgeries without any validity. For this reason, Swiss law prohibits taking pictures in private circumstances or using any photograph taken in public without authorization. Likewise, films must be taken in a specific context, (e.g., a bank robbery), for them to be admissible as evidence. Photographs and films may be employed to establish suspects' identity. Similar problems arise in the use of hidden microphones, tape recorders, and telephone eavesdropping techniques. All forms of voice recording pose the danger of violating the private sphere, of trespassing on private property, and of recording private statements without an individual's knowledge. Recording of public remarks is permissible. Recordings and telephone eavesdropping are only authorized for very serious crimes in progress (e.g., hostage situations). Use of various types of detectors (e.g., for metal and speed) and colored powder to apprehend thieves are regarded as acceptable. However, drugs and lie detectors are thought to infringe on the physical and psychological integrity of individuals; only taking blood samples for such purposes as determining blood alcohol levels is allowed. To protect personal information on computers, access to computerized police records has been limited, and linking police records with other computerized information systems is prohibited. Police-press relations remain a controversial area in police investigations. The need to consider the public freedoms and private interests threatened by proposed actions, to examine the legal basis for intervention, and to remember the limitations and inaccuracy potential of modern technical methods of investigation is emphasized. Notes are supplied.