I disagree. We will not know until the committal hearing (which by the sounds of it will be focused on the credibility of the victim through cross examination of her psychiatrist) as to whether there is a reasonable prospect of a conviction. At the moment there is a 'prima facie' case, however this could be negatived if the mental state of the victim is in question.
The police are not the arbiters of innocence or guilt. In such serious matters, the preferred option is to place the matter before the court to have the matter determined. Obviously there must be sufficient evidence as to warrant charges, otherwise police could find themselves facing extensive costs.
The conviction rate is reportedly between 40 and 60 percent for matters that are finalised with charges
http://www.lawlink.nsw.gov.au/lawli...$file/Sexual_offence_Information_sheet_06.pdf.
This case will come down, like most sexual assault cases, to the credibility of the victim...