report in respect of the applicant during this period to which it has been referred found, on 21 August 1995, after he had been detained for approximately one month, that he was healthy and that, despite his parents’ fears in this respect, there was no reason based on heart disease against his continued imprisonment (see paragraph 37 above). In these circumstances, the Court does not find it established that the conditions of Mr Assenov’s detention were sufficiently severe as to give rise to a violation of Article 3 of the Convention. 2. Alleged violation of Article 5 § 1 of the Convention 137. Mr Assenov alleged that his detention had been unlawful, contrary to Article 5 § 1 of the Convention, which provides (as relevant): “Everyone has the right to liberty and security of person. No one shall be deprived of his liberty save in the following cases and in accordance with a procedure prescribed by law: … (c) the lawful arrest or detention of a person effected for the purpose of bringing him before the competent legal authority on reasonable suspicion of having committed an offence or when it is reasonably considered necessary to prevent his committing an offence or fleeing after having done so…” He did not dispute that he had initially been detained for the purpose of bringing him before a court in compliance with Article 5 § 1 (c). However, he pointed out that the investigation into his alleged crimes had been completed by September 1995 and he alleged that thereafter his pre-trial detention had constituted a form of punishment, contrary to the presumption of innocence. Moreover, he reminded the Court that under Bulgarian law a minor should only be detained in exceptional circumstances (see paragraph 69 above). 138. The Commission noted that the time-limits contained in Article 222 of the CCP set restrictions on the length of any preliminary investigation but not of detention on remand (see paragraph 70 above). Article 222 did require that detention on remand following the prolongation of an investigation be confirmed. However, the applicant’s continued detention had complied with this requirement since it had been confirmed by the District Court on 19 September 1995 and by a number of decisions by the prosecuting authorities between October 1995 and October 1996. It did not, therefore, appear that the detention had been unlawful according to Bulgarian law or that there had been a breach of Article 5 § 1 on any other ground. 139. The Court recalls that the expressions “lawful” and “in accordance with a procedure prescribed by law” in Article 5 § 1 essentially refer back to national law and state the obligation to conform to the substantive and procedural rules thereof; but that they require in addition that any deprivation of liberty should be in conformity with the purpose of Article 5, which is to prevent persons from being deprived of their liberty in an arbitrary fashion (see, for example, the Erkalo v. the Netherlands judgment of 2 September 1998, Reports 1998-…, p. …, § 52). 140. In the present case the Court, like the Commission, finds no evidence that the applicant’s detention was unlawful under Bulgarian law. Moreover, it is clear that Mr Assenov was detained on reasonable suspicion of having committed an offence, as permitted by Article 5 § 1 (c).