Rights groups decry Greek investigation into migrant shipwreck that left more than 500 dead

The boat carrying migrants before it sank off the coast of Greece. Human Rights Watch and Amnesty International say the investigation into the incident is failing to make progress Photograph: Anadolu Agency/Getty Images

Human rights groups have deplored the lack of progress made by Greek authorities in their investigation into the controversial circumstances in which a migrant ship sank off the Peloponnese – leaving more than 500 dead – in one of the Mediterranean’s worst ever boat disasters.

Human Rights Watch (HRW) and Amnesty International claim there are credible allegations that the Hellenic Coast Guard’s “actions and omissions” contributed to the 14 June shipwreck.