This is one of the reasons why having adequate legal recourse is so important. The incompetence and inadequacy of the criminal justice system injures us all.
In an ideal world we would simply say "where is the evidence, this should be sorted out in a trial". But given that the cops are so hostile to sexual assault victims, forensics which aren't processed for decades (http://www.npr.org/2014/01/25/266275211/tested-at-last-rape-... ) and a legal system which will try the credibility of victims, it's hard to blame any sexual assault victim who shies away from reporting.
In an ideal world we would simply say "where is the evidence, this should be sorted out in a trial". But given that the cops are so hostile to sexual assault victims, forensics which aren't processed for decades (http://www.npr.org/2014/01/25/266275211/tested-at-last-rape-... ) and a legal system which will try the credibility of victims, it's hard to blame any sexual assault victim who shies away from reporting.
In the end, unanswered questions persist.