I know it's around here some place, but while I'm looking for it...

The anthrax letters do not show any obvious Gallicisms that would betray that they were from a fluent French-speaker, which Jdey presumably was. But they are consistent with a person who has acquired English as a second language, and there is nothing in them that is inconsistent with Jdey as author. In fact, Jdey is a highly believable author of the anthrax letters. Various objections that have been raised to al Qaeda authorship of the letters can be readily met. For instance, the concept of warning the target that he/she was being attacked was standard al Qaeda procedure in keeping with an injunction from The Prophet.

In fact, the author of the textbook (get it? the anthrax letters are literally a TEXTBOOK CASE for the practice of deducing a writer's language background from a very limited amount of text) argues very well that the author of the anthrax letters is NOT a second-language speaker of English. The writer instead shows a sophistication with the language (as he tries to simulate non-native speaker qualities, badly) that points to native speaker status.