Treaties — Application — Principle of non-retroactivity — Article 28 of Vienna Convention on the Law of Treaties, 1969 — Russian Federation ratifying European Convention on Human Rights, 1950 on 5 May 1998 — Polish prisoners of war killed on instructions of Soviet authorities in 1940 — Relatives of those killed complaining that Convention rights breached by Russian Federation — Whether Court having temporal jurisdiction to deal with complaint concerning procedural aspect of Article 2 of Convention — Procedural obligation to carry out an effective investigation under Article 2 — Separate and autonomous duty — Clarification of principles in Šilih — Procedural acts and omissions in period after Convention entered into force for Russian Federation — Whether genuine connection between killings as triggering event and entry into force of Convention in respect of Russian Federation — Whether two criteria satisfied — Whether lapse of time reasonably short — Whether major part of investigation taking place or ought to have taken place in period after Convention entered into force for Russian Federation — Whether connection which was not genuine sufficient in extraordinary situations — Convention values test — Whether need to ensure real and effective protection of guarantees and underlying values of Convention — Whether Court upholding respondent Government’s objection ratione temporis

Human rights — Right to life — Procedural obligation to carry out an effective investigation under Article 2 — Separate and autonomous duty — Whether Court having temporal jurisdiction to deal with complaint concerning procedural aspect of Article 2 of European Convention on Human Rights, 1950

International criminal law — Treaties — Application — European Convention on Human Rights, 1950 — Serious crimes under international law — War crimes — Katyn massacre — Whether killings negating foundations of Convention — Whether creating necessary connection between killings as triggering event and entry into force of Convention in respect of Russian Federation — Whether procedural obligation under Article 2 of Convention coming into effect — Whether Court having temporal jurisdiction to deal with complaint concerning procedural aspect of Article 2 of Convention

Treaties — Application — Human rights treaties — European Convention on Human Rights, 1950 — Convention coming into existence on 4 November 1950 — Serious crimes under international law in 1940 — Whether Convention values clause applying to events occurring prior to adoption of Convention — Whether condition met for procedural obligation under Article 2 of Convention to take effect — Whether Russian Federation obliged to carry out effective investigation

Human rights — Prohibition of inhuman or degrading treatment — Prolonged denial of historical fact — Withholding of information from victims’ relatives — Whether suffering of victims’ relatives having dimension and character distinct from inevitable distress stemming from violation itself — Whether applicants uncertain about fate of their relatives — Whether Russian Federation violating Article 3 of European Convention on Human Rights, 1950

Human rights — Obligation to furnish all necessary facilities for Court’s investigation — Failure to provide Court with requested document — Relevance of domestic top secret classification — Whether Court considering document necessary to establish facts in case — Effective operation of system of individual petition — Whether obligation could be enforced irrespective of outcome of proceedings — Whether Russian Federation violating Article 38 of European Convention on Human Rights, 1950

Evidence before international courts and tribunals — European Court of Human Rights — Assessment by Court of admissibility, relevance and probative value of evidence — Contracting States having obligation to furnish all necessary facilities to Court — Effective operation of system of individual petition — Proper and effective examination of applications — Respondent Government failing to provide document — Relevance of top secret classification at domestic level — Whether Russian Federation failing to comply with its obligations under Article 38 of European Convention on Human Rights, 1950

Treaties — Interpretation — Application — European Convention on Human Rights, 1950 — Internal law and observance of treaties — Article 27 of Vienna Convention on the Law of Treaties, 1969 — Top secret classification of document in domestic law — Respondent Government using domestic legal impediment as justification for not furnishing requested evidence — Whether permissible — International responsibility of Russian Federation — Whether Governments answerable under European Convention for acts of any State agency — Relevance of national security concerns — Whether Russian Federation failing to comply with its obligations under Article 38 of European Convention on Human Rights, 1950

War and armed conflict — Prisoners of war — Murder by forces of detaining State — Katyn massacre of Polish prisoners of war by Soviet forces — Whether engaging obligations of Russian Federation under the European Convention on Human Rights