You have not expressed this correctly and have not quoted the transcript of judgement from the High Court.
It is not based on "probability". The "guilt" must be beyond reasonable doubt and the Defence was unable to demonstrate that there was no "reasonable doubt". They were considered not have been able to do so, thus couldn't be deemed to be guilty. A guilt verdict has to water tight. If not, then considered "innocent" despite the fact he may well not be so. The case was not considered strong enough to establish "guilt".
