I don't strongly endorse that idea. In fact, my original take was that they'd made up one letter (to AMI) and decided to trot down to the Boca Raton post office to buy another packet of 6 letters to send to the other addresses.
BTW, these people were normally very frugal in their behavior so they didn't have a large box of envelopes or a sheet of postage stamps. Instead, they could buy embossed envelopes as needed at the post office and avoid waste.
That's why the AMI letter took one route while the others simply got "lost in the mail" until they were discovered in supposedly empty equipment in New Jersey (and on different days no less demonstrating they were in different containers, and in a size where the commercial mailer only needed a few per week).
Now, why the AMI letter? This gets to the heart of why a letter went to the New York Post as well, and none went to Chicago Tribune, New York Times, Washington Post and so forth.
These guys are from the Middle East. There the premier newspapers are TABLOID SIZE. Same with India, Pakistan, China, etc., etc. The THIRD WORLD lives on tabloids.
In America the premier newspapers (if you think tabloids are "it") are sold at grocery store checkout lines. AMI dominates the racks.
To an outsider with a limited command of English, and limited time to read newspapers, these tabloid newspapers stand out as "the thing" to read. And, in the Middle Eastern mind they really must be considered to be America's foremost newspapers.
They are everywhere. Everyone knows what they are. People who've never seen a NYTimes have read Star.
If you want to make a truly massive biological attack on America's news media, it's pretty obvious to me that you'd attack AMI itself, and there it was, conveniently located right where they lived in Boca Raton!!!!!
I really do wonder if any of these guys had any idea what the NYTimes is.
The letter directed to Tom Brokaw, if mailed in Florida, would be routed through a major airport and main post office for the financial capital of the world. The letter directed to the two Senators would be routed through a major airport and the main post office supporting mail service for the entire United States government (insofar as headquarters/cabinet operations were concerned), and into the Congress itself.
In sort, the attack went after the major media (AMI), the center of world Capitalist enterprise, and the capital of the United States.
Makes a lot of sense.
And to the funny little foreign guys, the New York Times means nothing whatsoever. they can't read it easily, it has no cartoons, and they never publish any pictures of scantily clad women.
A little harder question is "why Leahy, Daschle and Brokaw"?
Here the answer is remarkably simple. A few weeks before the attack a website called "www.jewsforlife.org" ran a newsletter type piece that had their names and addresses in them, and in the same format those addresses were used in the attack letters.
I think the terrorists wanted us to believe that "the Jews did it".
You will find one or more such boxes in every commercial district. No one is watching them after hours. Besides, no one is going to be concerned if a carload of Arabs pulls up to a street collection box and drops in a letter (before 9/11).