Irish horserace trainer Gordon Elliott has admitted that an image circulating on social media of him sitting on a dead horse is genuine and apologised for "any offence caused".
The disturbing imaged showed Elliott, a three-time Grand National winner, sitting on a dead horse at a training yard while making a phone call.
Elliott, 42, said he was "cooperating fully" with the Irish Horseracing Regulatory Board which has launched an investigation into the image.
"I apologise profoundly for any offence that this photo has caused," Elliott said.
Elliott tried to provide context for the image.
"The photo in question was taken some time ago and occurred after a horse had died of an apparent heart attack on the gallops.
"At what was a sad time ... my initial reaction was to get the body removed from where it was positioned.
"I was standing over the horse waiting to help with the removal of the body, in the course of which I received a call and, without thinking, I sat down to take it.
"Hearing a shout from one of my team, I gestured to wait until I was finished ... Such background information may seem trivial at this time ... However, I feel it is important to provide people with some context surrounding this photo."
An IHRB spokesman said on Sunday: "The investigation is ongoing and will be dealt with as quickly as possible."
The British Horseracing Authority (BHA) said it was aware of the image and officials are in contact with their Irish counterparts.
Elliott said he was cooperating fully with the IHRB's investigation.
