Sydney trainer Con Karakatsanis and his father Tony have been found guilty of planning to administer an illegal raceday treatment to Howmuchdoyouloveme before he raced at Flemington on November 3.

Neither Con nor Tony Karakatsanis, a licensed stablehand, attended Tuesday's verdict in the long-running inquiry.

Judge Russell Lewis, chairman of the Racing Appeals and Disciplinary (RAD) Board, said the board was satisfied that each of the five charges laid against the Karakatsanises had been proven.

The Board will hear submissions on penalty next week.

Judge Lewis said the case was largely circumstancial and the credibility of witnesses was paramount.

He said the Karakatsanises were found to be "unreliable witnesses".

The two were found guilty of a combined five charges relating to the discovery of stomach-tubing equipment in the stable of their horse Howmuchdoyouloveme hours before it raced at Flemington.

Stewards found the equipment, including a saline and electrolyte mixture used for rehydration, in a chaff bag.

Tony Karakatsanis admitted he put the bag of tubing equipment in the horse's box, but that he thought it was a bag of hay when he picked it up in the stable's feed room.

He told the hearing he and his son had prepared a saline drench that was to be administered to Howmuchdoyouloveme after it raced.

Howmuchdoyouloveme, favourite for the Yellowglen Stakes, was allowed to run but finished out of the placings.

Judge Lewis said the Board was "comfortably satisfied" that Tony Karakatsanis knew the bag contained tubing equipment and had the time and opportunity to carry out the tubing of the horse had stewards not arrived.

It is against the rules to administer any treatment to a horse on raceday.

The Board was also satisfied Con Karakatsanis was in the process of locking the gates to the stable when Racing Victoria's Compliance Assurance team turned up unannounced.

They were also satisfied that Tony Karakatsanis, with the prior knowledge of Con, had intended to stomach tube Howmuchdoyouloveme on raceday before leaving the stable.