The site of a possible 19th century Persian corpse

I ran out of steam with Persia, The Great Game and Sir Percy Sykes. Two bits of information stay in my mind: one is that polo is a Tibetan word meaning a ball made from willow; the other, that there may be the corpse of a Persian servant strangled by his employer with piano wire buried in the garden of Buckingham Palace.  As it happens, I have been a guest there and, had I known of this fascinating possibility I would have asked my hosts if they were aware of it.  I was there as a member of the London branch of the Royal Forestry Society, with a handful of others. We were admitted at a side entrance, expecting to have a guided tour of the trees in the garden.  We were milling about on the lawn, when we saw the Queen and the Duke of Edinburgh coming down the steps.  We were invited in for a drink and some twiglets.  Extraordinary.  It may be that meeting the Queen had been anticipated by the organisers, but, if so, we ordinary members had not been warned.  It was in the days of the IRA and Lord O'Neill was among our number, so perhaps that was the reason.