The Commission of Inquiry into Australia's equine influenza inquiry has so far failed to establish the identity of the mystery horse, which attended an event in Maitland, in the New South Wales Hunter Valley, during the crucial hours when equine influenza took hold in the state.
It is widely accepted that equine flu somehow made it to the event at Maitland in August and was spread about the state, and as far as Queensland, when competitors took their horses home.
The inquiry, headed by retired High Court judge Ian Callinan, is keen to identify the horse to determine what, if any, link it had to the outbreak.
However, an appeal on December 13 for the owner to come forward - even anonymously - has so far failed.
Several competitors told of a coughing horse but could not identify it.
A witness told the inquiry: "During the night, I was feeling pretty restless. I got up around about 11 o'clock ... there was still a bit of a party happening.
"Before I went over, I heard a horse coughing. The sound seemed to be coming around about the centre of the yards, so to speak, coming from that general direction.
"I heard it (again) later on in the night."
The witness told of two or three dry-sounding coughs.
"It was a bit of a dry cough, but not a cough that would be uncommon at a horse event. Quite often, you'll go to a horse event and you'll hear horses coughing, maybe from dust or dry feed. But, in saying that, I'm not a vet; I don't know what it was from or anything."
At the conclusion of the day's hearing, counsel representing New South Wales, John Agius, suggested an appeal for the owner of the coughing horses to come forward would be appropriate.
"It is likely that the person who had a coughing horse at Maitland now recognises that that horse is of some significance. It may be that such a person is feeling concerns about coming forward," Mr Agius said.
"I wonder whether the Commission would be prepared to go so far as to let the public know that the Commission has power to take evidence in private ... in order to protect such a person, should they feel that they may in some way be prejudiced.
"I wonder whether any such person also ought to be informed that nothing that they said here, provided that they told the truth, either publicly or in private, could be used against them in civil or criminal proceedings.
"It may be that this individual doesn't recognise the importance of this evidence to this inquiry and sees the evidence only from their own point of view. Perhaps some assurance along those lines might assist them in coming forward."
After further discussion, Commissioner Callinan said: "I should make it clear that I would be prepared to entertain anonymous submissions of evidence."
He went on: "I can't give any assurance that those submissions would definitely be accepted, but they might very well be, and I would certainly be prepared to entertain them and to give consideration to them."
Mr Agius: "No doubt it would be of great assistance to the inquiry if members of the press were able to report those last remarks of yours."
Despite the appeal, the identity of the coughing horses remains a mystery.
The Commission of Inquiry is continuing.