Nutty - you said: "I'm sure that having spent money on buying the horse the last thing the owner intended to do was to drown it."

You are probably correct - but if you read the reports, you will see that the horse did not belong to the man who was riding it in the river. He had been told (possibly BY the owner) not to take it in the river, as it wasn't used to it. However, he saw fit to take the horse anyway (twocking a horse???) and swim it. This, I suspect, is why he did a runner when it all went wrong and the horse was drowned. Perhaps he suspected he'd get a 'jolly good telling off' by the owner of the (now) dead horse? Perhaps he has had one. Perhaps he is still legging it???