Celebrated Irish racehorse trainer Gordon Elliott says he’s sorry about a photograph of himself sitting atop a dead horse’s body that went viral. “The photo in question was taken some time ago and occurred after a horse had died on the gallops,” he tweeted after being pilloried worldwide for the callous picture. “I was standing over the horse waiting to help with the removal of the body, in the course of which, to my memory I received a call and, without thinking, I sat down to take it.” The Irish Horseracing Regulatory Board says it is investigating. The British Horseracing Authority says it is “considering its own regulatory options.” “People who work in our industry believe their values—of caring for and respecting our horses—have been deeply undermined by this behaviour,” the BHA said in a statement. “On their behalf, and on behalf of all horse-lovers, we say loudly that British horseracing finds this totally unacceptable.” Betfair, an online betting site with which Elliott has been affiliated since 2016, announced Monday that it has ended its relationship with the three-time Grand National-winning trainer. Elliott says he will be “cooperating fully” with investigators.