In criminal prosecutions the crown attorney must prove the guilt of the accused beyond a reasonable doubt. Where the judge finds that there is a doubt as to the guilt of the accused, the judge may dismiss the charge.
A skilled criminal defence lawyer shall then look at all aspects of the police investigation and guilt of the accused to present all the facts to the judge to present evidence that may shed doubt on the case. The defence does not have to prove the accused one hundred percent innocent, only to put doubt of the guilt before the court.
Judge ruled there was reasonable doubt. The accused tried to provide sample but was unable to.