Clues sparse in anthrax investigation

NEW YORK (CNN) -- Tracing Kathy Nguyen's steps using her subway card has yielded "no smoking gun" aimed at the source of the anthrax bacteria that killed her, authorities say, but the already exhaustive investigation will go on.

The next step, they say, will be to test the subway itself.

"We're going to look at subway stations that might be along her route, and the CDC will work with us, and we'll put forward a methodology to test that as well," said New York City Health Director Dr. Neal Cohen. The CDC, or Centers for Disease Control and Prevention, is the nation's public health center.

VIDEO CNN's Gary Tuchman reports on the mystery surrounding the anthrax death of Kathy Nguyen (November 8) Play video (QuickTime, Real or Windows Media)   MORE STORIES Four N.J. postal stations positive for anthrax  Anthrax survivor: 'They can't possibly win'     IN-DEPTH  VIDEO/AUDIO   •  Investigators baffled by 94-year-old woman's death  MORE STORIES   •  Gephardt: Anthrax cleanup 'tougher than expected'   •  Official: CIA uses anthrax, but no link to letters  EXTRA INFORMATION   •  Anthrax symptoms   •  Tracking the bacteria  RESOURCES   •  Advice on suspicious packages   •  Message board Anthrax by the numbers 17 total anthrax infections   -- 10 cases inhalation anthrax (4 dead)   -- 7 cases cutaneous anthrax Source: CDC/CNN

Nguyen is the only anthrax victim with no established connection to any known contamination. The 61-year-old hospital stockroom employee died October 31, after entering the hospital three days earlier.

Investigators say they have not ruled out a link between Nguyen and one of three anthrax-laced letters postmarked in New Jersey, or perhaps another contaminated letter that has yet to be found.

Seventeen people have contracted the potentially deadly disease -- including 10 who inhaled spores and developed inhalation anthrax, deadlier than anthrax caught by skin contact. Nguyen and three others who contracted inhalation anthrax, including two postal workers at Washington's Brentwood processing facility, died.

Some 32,000 people have started an antibiotic treatment after a potential exposure to anthrax, according to a CDC report released Thursday, and about 300 facilities have been tested for the bacteria. Most of those affected are postal workers and postal facilities.

Just as the investigation into Nguyen's case has yet to uncover the source of her infection, the anthrax investigation at large has yet to come close to finding out who sent the contaminated letters. President Bush, in Atlanta, Georgia, Thursday evening, said the act was as "uncivilized" as the September 11 hijacked airliner attacks.

"The second attack against Americans came in the mail," Bush said. "We do not know whether this attack came from the same terrorists. We don't know the origin of the anthrax, but whoever did this unprecedented and uncivilized act is a terrorist."

Investigators have stumbled over roadblocks tossed in their way by hoaxers who have mailed packages and letters containing little more than talcum powder. The FBI has responded to more than 2,500 false anthrax threats, although some of those have been legitimate false alarms.

The FBI said Thursday that packages sent to as many as 200 clinics that provide abortion services -- including Planned Parenthood affiliates -- did not contain anthrax, as the senders claimed.

The National Abortion Federation said the packages were signed from "The Army of God," which it called a domestic terrorist group.

Three people were indicted or charged Thursday with perpetrating an anthrax hoax, including 52-year-old postal worker Clarence Lindsey in Cicero, Illinois. He allegedly sent a package to a local resident on which he wrote "Antrax Inclosed (sic)."

Legislation introduced in the Senate Thursday would impose a five-year prison sentence, $10,000 in fines and restitution for any disruption caused by a false terrorist threat or a report of such a threat.