PART IV.  POLICING SITUATIONS • Surveillance • Door-to-door inquiries • Line-up • Suspect interview The only legitimate aim of employing these methods is to collect information in order to establish the truth. Each investigative method should be provided for in the law, usually in the Criminal Procedures Code or equivalent piece of legislation, and should only be used for a particular, wellspecified, purpose. It should be carried out in such a way that it causes minimal harm to person and property, and interference with affected people’s human rights should be limited to a minimum.286 Most investigative methods will have an impact on the human rights of the suspected invididual, including his or her right to privacy, as well as that of others with whom he or she may have had contact. Law enforcement officials normally will need to obtain the authorization, on a case-by-case basis, of either a higher ranked law enforcement official or from a judge or prosecutor, depending on the measure and the domestic criminal justice system.287 As a general rule, the more intrusive the method, the higher authorization there should be, with the most intrusive methods being subjected to independent assessment by a judge. Law enforcement officials may use force to: • Protect a scene of crime • Preserve or seize evidence • Prevent destruction of evidence In addition, force may be necessary to restrain an individual who is opposing, for example, a house search. Restraints should only be used when necessary, and in a manner that is proportional to the objective sought and the resistance encountered. Force also may be used in order to get physical access to information, for example where force is required to open a door in order to access a house that is subject to a search warrant. In all cases, the use of force should be restricted to what is necessary and proportionate. It can never be a legitimate policing objective to intimidate or punish. Law enforcement officials are never allowed to use force against a person in order to collect information, such as when interviewing suspects, victims, relatives of the alleged offender, conducting a door-to-door inquiry, meeting with informers and so forth in order to get information. Not only is this unlawful, it may amount to torture or ill-treatment and may have criminal and disciplinary repercussions. It is also ineffective as information collected in violation of criminal procedure rules and, in particular, confessions or witness statements obtained under torture or other ill-treatment, may be inadmissible as evidence in criminal proceedings. Evidence collected through torture or ill-treatment can be used against the law enforcement official collecting the information in such a manner. 286  See United Nations Human Rights Committee General Comment No. 16, para. 8; searches of a person’s home should be restricted to a search for necessary evidence and should not be allowed to amount to harassment. 287  See United Nations Human Rights Committee General Comment, No. 16, article 17, para. 8. 129