Although DNA analysis showed the samples given in Goulburn were essentially a match, it did not say whether the urine in either belonged to Brown, Rando or someone else.

It is believed the two drivers have since provided follow-up samples which have been sent to the laboratory in Melbourne.

Brown had been suspended after the race meeting at Goulburn after failing to provide a second vial of urine on the racecourse when asked to do so by stewards, who had deemed his first sample to be of insufficient volume.

That order was lifted two days later, with Brown allowed to return to the track, when testing confirmed the sample he provided was free of banned substances despite the low volume.

According to Australian harness racing rules, a driver commits an offense if they refuse to supply a sample as instructed by stewards, “or tampers, defaces, alters, substitutes or in any way obstructs the collection of such sample or attempts to do any of those things”.

Prohibited drugs on race day include cannabis, stimulants such as cocaine and benzodiazepines, while alcohol is also prohibited at a breathalyzer reading of more than 0.02 percent.

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The circumstances surrounding Brown and Rando’s temporary suspension are believed to be the first in harness racing in the state.

There has only been one recent episode of drug test manipulation in thoroughbred horse racing in NSW. It occurred a decade ago when jockey Josh Adams pleaded guilty at an inquiry by Racing NSW stewards to breaching testing rules by using fluid in a container he had hidden in his clothing as a substitute for a urine sample. He was suspended for two years.

2015, Parramatta Eels forward Kenny Edwards took a drug test on behalf of teammate Kaysa Pritchardwho told officials he had been concerned about ingesting a sleeping pill that had not been issued to him by the NRL club doctor.

Pritchard was later instructed to provide a sample for pre-season testing by the NRL and both players returned clear.

Edwards was banned for nine months by the NRL for breaching testing protocol.

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