I'm no longer sure of that. By the time the second wave of mailings had been done, the first wave had caused fatalities.
If the letters were only for "publicity",the death of Robert Stevens in Fla. should have brought the mailings to a halt...but they continued.
100% of the whole deal can be explained with a single mailing of about 6 letters at the Boca Raton, FL post office, probably in one or more street collection boxes on the evening of September 7, 2001, or anytime on September 8, 2001.
The strange distribution pattern and delays are readily attributed to the ordinary handling hand addressed, single-piece rate, First-Class mail receives when not otherwise sent to a credit card company or utility.
The attack was totally successful from the perspective of the terrorists. The main post office serving America's capital city was shut down. The most important periodicals in America lost their editorial offices.
In a typical third-world country, this would spell economic and social disaster ~ might even precipitate a popular uprising and civil war.
In the United States it caused us to reroute the mail and find a new office.
The attackers had also planned to take out several major airports, but due to the mishandling of this mail in Boca Raton, none of it actually went through those airports. Instead, it was carried by surface the whole way!