I'm wondering if the same person who sent it to the constituent also helped it "make its way to the Missouri Democratic Party".
I'm smelling a set-up, either by a 'Rat mole in the Rep's office or else by the 'constituent' who may well turn out to be a DailyKos addict. Why would a copy of the letter "make its way" to the Democratic Party unless the recipient had a real axe to grind with the Rep? They should not have taken responsibility unless they were provided with the original document so they could examine it - hope that was done.