The FBI did not have the appropriate translators during the initial hours after OKC. They had to borrow 10 Arabic translators from the Pentagon.
Immediately after the bombing on a Wednesday, the FBI requested the translators be sent to OKC. By Friday, the FBI had changed its mind (and story), and sent a message to the military that the translators were no longer needed. By Friday, "John Doe #2" was the culprit.
I may have a few of the details wrong, such as when the translators were sent back. And I don't have time right now to reread my post from 2002, but here it is if someone is interested:
http://www.freerepublic.com/focus/news/719338/posts?page=41#41
The info about those 10 Arabic translators is in red at reply 41.