An investigation into the death of a stallion at Appleby Horse Fair is moving forward.
Dan St Quintin, of Cumbria police, is gold commander for the annual event, said the RSPCA was leading on the investigation but new lines of enquiry had emerged and people had come forward in relation to the incident.
The horse, a three-year-old 14hh skewbald trotter, collapsed at Jubilee Bridge at around 3pm on Wednesday June 5.
Investigators said it had been pushed to the point of exhaustion.
The RSPCA released CCTV images of a man it said it was keen to identify in connection with the incident.
RSPCA chief inspector Rob Melloy said: “The horse’s temperature was very high, and he was covered in rubs. He had been worked until he dropped.
“This was an inexcusable act of cruelty. This person has let themselves, their family and of course this poor horse down, who undoubtedly suffered before he died.
It is currently not known who owned the animal and Insp Dan St Quintin said investigators were hoping to identify them to determine if a crime had been committed.
After the horse was found, Gypsy representatives Billy Welch and Bill Lloyd said: “We condemn in the strongest possible terms whoever has done this.
“We are sickened and saddened by the cruelty that this person or persons have shown. We have no hesitation is asking anyone who has any knowledge of this awful event to cooperate fully with police and RSPCA in identifying whoever is responsible.
“If you are in any doubt, please come forward and provide any information you have for the sake of justice and the future of the fair.
“We are fully supportive of the efforts of the RSPCA and their partner charities to improve the standards of horse welfare, and this is a body blow to all our efforts. As far as we know we have never had this happen before and we plead with everyone to listen to the welfare messages so that it never happens again.
“Appleby is one of the greatest celebrations of the horse in Europe and this tragic event is a stain on the fair that will be hard to wash out.
“The fair attracts a diverse mix of people including Gypsies and Travellers, but the majority are settled people.
“The standard of horsemanship among Gypsy people is usually high and they are often among the first to report abuse at the fair when they see it.
“We do not yet know the identity of the person responsible and if it was a Gypsy we will condemn them even more strongly and loudly but please do not leap to any conclusions until we know the facts.”
Ch Insp Melloy said if the RSPCA or other official body spot an exhausted horse, they will perform an exhaustion test.
He added: “If the horses fail a test, it could lead to prosecution. If people are asked to slow down, they should do it.
“The majority of people here are absolutely brilliant at looking after their horses, it’s just a minority of people, either through ignorance or malice, who mistreat their animals.”