TSALIKIDIS AND OTHERS v. GREECE JUDGMENT 27 or in obtaining witness statements while recollections are sharp. Reasonable expedition will remain a requirement, but what is reasonable is likely to be coloured by the investigative prospects and difficulties which exist at such a late stage (see Brecknell v. the United Kingdom, cited above, §§ 71-72). (b) Application of the above-mentioned principles in the present case 91. The Court notes at the outset that the parties have devoted a large part of their submissions to the alleged deficiencies in the initial investigation, focusing mainly on the alleged omissions of coroner G.D.L. In view of the conclusion as regards the applicants’ failure to observe the six-month rule under Article 35 § 1 of the Convention in respect of their complaints concerning the initial investigation, the Court will not deal with those arguments. 92. The Court will therefore examine whether the information provided by the applicants to the domestic authorities on 8 February 2012 amounted to the kind of new evidence which would entail the revival of the procedural obligation to investigate. In this connection the Court observes that a new investigation was started into the applicants’ allegations by the authorities, who thereby discovered new leads and information about the killing. Furthermore, it is to be noted that, in the proceedings before the Court, the applicants not only challenged the effectiveness of the investigation carried out between March 2005 and June 2006, but also the effectiveness of the investigation conducted after February 2012. 93. In the light of the foregoing, the Court considers that the information submitted to the authorities by the applicants in February 2012 resulted in significant new developments and, as such, the procedural obligation to investigate the killing of the applicants’ relative was revived after that date (see Gasyak and Others, cited above, § 63; see also, mutatis mutandis, Kavak v. Turkey, no. 53489/99, §§ 84-90, 6 July 2006). 94. The Court notes that, following the applicants’ request for reopening the proceedings, a supplementary investigation was conducted by the public prosecutor’s office without delay. The supplementary investigation resulted in the decision of 16 June 2014 not to initiate criminal proceedings and to uphold the conclusions of order 80/06, by which the initial investigation had been closed (see paragraphs 18 et seq. above). 95. It is clear to the Court that the supplementary investigation was reasonably prompt, as it was instituted immediately after the applicants’ request for reopening, and lasted about two years. The Court also takes note of the fact that the entire investigation was conducted by the public prosecutor’s office, an authority which was institutionally independent, and that the applicants were involved at the various stages of the proceedings – by having their technical advisor present during exhumation, for example. 96. It remains to be examined whether the investigation conducted was effective in the sense of being capable of ascertaining the circumstances in