ecution. Articles 6 and 7 oblige States Parties to take specific measures in that regard. States are required to detain any persons suspected of committing acts of torture as referred to in Article 4 found in their territories, when they are “satisfied, after an examination of information available to them, that the circumstances so warrant”, or to take other legal measures permitted by law and in the circumstances deemed as necessary to secure the continuing custody of the accused. States have a wide degree of freedom in assessing whether the circumstances justify pre-trial detention. This assessment depends in part on the domestic rules concerning evidence.149 Under the State’s own laws, there may exist time limits for custodial measures. However, these limits should not make it impossible to obtain extradition or prosecution of the accused. Custody and other legal measures should not be for excessively lengthy periods, but only for the period of time required for criminal or extradition proceedings to be instituted. It is not obvious what elements are sufficient to trigger the obligation to investigate and possibly prosecute a suspected torturer. It must be assumed that, while there is an obligation to initiate a preliminary investigation into the facts, a certain minimum of probability that torture has been committed must exist for an investigation to be launched. The Convention does not provide a minimum threshold for the obligation to investigate. It must be assumed that the decision to start an investigation will be made according to the general criteria in this regard laid down in national laws for similar serious crimes. § 3. Each detainee must be offered assistance in contacting the nearest authorised representative of the State of which he or she is a citizen. If the person in custody is by legal definition stateless151, i.e. is not considered as a national of any particular State, he or she should be assisted by the authorities of the country where he or she is resident most of the time, or the place where he or she has acquired a residence permit. The person in custody must not be forced against his or her will to contact the concerned national authorities, but should be given the option to do so. § 4. The State Party must immediately notify States which have or may have jurisdiction over the offence of any of the grounds referred to in Article 5 §1, i.e. States having jurisdiction over any territory where offences are committed, when the alleged offender is a national of such States, or when the victim is a national of such States. This obligation applies irrespective of whether the holding State intends to prosecute or extradite. The information transmitted must contain a II. INDIVIDUAL ANALYSIS OF ARTICLES 1–16 OF THE CONVENTION 2. ANALYSIS OF SUBSTANTIVE PROVISIONS § 2. States Parties are obliged immediately to initiate a preliminary investigation into the facts. This obligation applies primarily when the State itself will be prosecuting the suspect. After all, if a suspect is to be extradited, the State requesting the extradition will usually carry out such an investigation.150 43