My ex a convicted felon used our daughter's identity. Why will the State or feds not prosecute?

My ex was convicted of id theft in 2005. Child protection, cops and Courts knew she has also used our daughter's identity. April 2009 the sheriff investigated. His report lists my daughter has a fake social security number, open and charged off accounts and a fake birth date on her credit report. It was turned over for prosecution but my ex had a relationship with the prosecutor. No prosecution of a felon for id theft, fraud, theft b deception and theft of services. Child protection had the court seal the records because they don't want the documents public. Local attorneys don't want to get involved because the Judge in the matter hates me. Why no prosecution of federal and state felonies by a convict?
It is on a blog an the State hates it. http://southdakotagov.wordpress.com/2009/07/06/sheriffs-report/