Surrey Police said the matter has now been formally passed to the coroner and an inquest will be held after finding no evidence of foul play. This was despite two post-mortem examinations carried out in November failing to establish Alexander Perepilichnyy's cause of death.
Toxicology samples were also taken from both post mortems but the results have not been released.
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The 15-year-old from Grays in Essex was killed after a fight started at a birthday party.
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