MISSOULA, Mont. -

“Frustration, disbelief and outrage,” that's the reaction from Missoula County Attorney, Fred Van Valkenburg, in the wake of a published letter from federal prosecutors.

The letter, released last Friday, outlined Department of Justice Arguments against county prosecutors, and how they handle sexual assault and rape cases.

Friday, Van Valkenburg fired back, defending his department’s effectiveness and accusing the DOJ of using last week's letter as "retaliation" for his court challenge against them.  He claims the DOJ’s actions are a "politically calculated and irresponsible move".

After 18 months, the County Attorney writes that the feds still have not provided any specific information backing up their statements.

To read the full text of Van Valkenburg’s letter, click here.