In certain situations, such as trials, they now try to use two translators or interpreters. Actually, they are supposed to use three, two of whom take turns while the third one supervises for accuracy and adherence to standards. However, in the translation of written documents, particularly considering the volume of documents and the small number of Arabic or Farsi translators, the work is usually done by one person (although I would suspect that a document for the NSA was reviewed and edited by more than one person).
There have been instances, including in the State Dept., of translators wilfully mistranslating or not translating, however. It's something worth noting.
There needs to be a housecleaning there. And these people are nuts if they think they're doing peaceful Muslims any favors. What they're doing is like somebody nice-ifying Mein Kampf so that you can't tell the difference between it and something written by Rush Limbaugh or Jimmy Carter.
There are MANY Iranian born Jews in Los Angeles and New York who are now citizens that be trusted with such matters of translating without treason or deceit.
There are also a handful of Iranian Christians that are converts from Islam who could do an even better job.