CBS News correspondent Bob Orr and producer Robert Hendin report the following from a U.S. law enforcement source:
The FBI's "suspicious letters" case has gone international. Letters containing white powder have begun showing up at "a handful of U.S. embassies abroad." One of the letters was received at the U.S. Embassy in Germany.
The letters seem to be nearly identical to the white powder letters that have been sent to more than 30 governors' offices in the U.S. since October. All of the mailings contain a non-hazardous powder and a vague generic one line threat. And, all of them have been postmarked and sent from the North Texas area.
Law enforcement officials say this letter campaign is an obvious hoax that is not a danger in and of itself, but the investigation is time-consuming and taxes already thin resources.
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Kevin Hechtkopf is CBSNews.com's politics editor.