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.
The death of a Russian supergrass who was a key witness in a multi-million pound international fraud investigation is not suspicious, police said today.
Alexander Perepilichnyy, 44, was found collapsed outside his home in Granville Road, Weybridge, Surrey, on November 10 last year sparking a major police investigation over fears he had been poisoned.
He was involved in a fraud case involving the theft of around £140m in tax revenue from the Russian government at the time of his death.