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.
This is an election year, so security is going to have to be tight - even on things like this, I guess. *sigh*