Still, Mayor Giuliani criticized the FBI for being slow to react. The two agents who showed up at NBC normally were assigned to investigate drugs. They had no idea anthrax might be involved and treated the case like an illicit drug case. Without explanation, they were told that O'Connor was not available to be interviewed. The agents put the letter in an evidence vault instead of having the powder tested. They waited until they could interview O'Connor.
Subsequently, O'Connor developed anthrax from the second letter. On October 6, one of her doctors notified the city health department, which notified the FBI. Only then did Barry Mawn became aware of the delay in investigating the first, bogus letter. He made sure the powder was tested immediately. Since that letter turned out to be a hoax, the delay did not make any difference.
The call from NBC about the first letter was "one of maybe about eight thousand leads we had received," said Mawn, who was working eighteen-hour days, seven days a week. "The letter should have been sent to headquarters for immediate testing. The agents who normally pursue drug cases handled it like a drug case," he said.
At the Washington Field Office, Van Harp pursued three theories: that the anthrax letters came from al-Qaeda, from a domestic right- wing terrorist group, or from a lone suspect like the Unabomer. After a month, the bureau had developed enough investigative information to suggest that this last possibility was the right one. As the investigation into the airplane attacks began to wind down, Harp had practically the entire office of 659 agents working the anthrax case.
In the middle of it, Al Kamen of the Washington Post noted that an FBI advisory warned citizens to look for indications that a letter or package might be suspicious and might contain anthrax or a bomb. The indications might include excessive tape or string, protruding wires, no return address, or a strange odor. Recipients should also be on the lookout for misspelled words, the poster said. In addition, the FBI advised recipients to check to see if it's "Possiblly sic mailed from a foreign country."
"Yikes!" Kamen commented. "They've taken over the FBI!"
In the months leading up to the September 11 attacks, the CIA, whose job it is to spy overseas, and NSA, which intercepts communications, had been picking up fragmentary intelligence that al-Qaeda might be planning another attack on U.S. interests. An intercept picked up Osama bin Laden telling one of his four wives to return to Afghanistan immediately. "There is a big thing coming," an al-Qaeda operative said.
"There was general intelligence that al-Qaeda was up to something," Mawn said. "We heard the drums beating. There were specific threats about Yemen. We thought there might be an attack overseas."