Barring the discovery of any ready explanation for her illness, or the surfacing of a new anthrax letter, federal investigators say they'll have to start from scratch on the latest New York case and attempt to recreate how the victim may have crossed paths with the disease. So far they have few clues.
There's no river of letters to follow, for example, like the one in Washington. In the capitol, where new anthrax discoveries seem to occur almost hourly, investigators at least thought they had a plausible explanation--that somehow numerous letters and post offices had been cross- contaminated by the same highly potent anthrax letter sent to Senator Tom Daschle. But none of that would explain the New York victim.
"Clearly, she was not a postal employee. How she became contaminated and how she became infected is something we need to try to find out," said Tom Ridge, director of homeland security.
One explanation is that there may be more anthrax letters out there than have been discovered.
To find out, the FBI is about to start sorting through between 300,000 and a million pieces of unopened mail that were seized from Capitol Hill after the Daschle letter was found. Now stored in 80 sealed 50-gallon drums, the letters will be inspected this week in an airtight warehouse near Washington.
Meanwhile, investigators say they have developed "several potential leads" in the case but have "no specific suspects."
And there is news tonight that only adds to the pressure to find the source of the anthrax attacks.
There is a new assessment of just how powerful, and how potentially damaging, the anthrax was in the letter sent to Senator Daschle.
Republican senators were told today that the anthrax in the letter received by Senator Daschle last week was "so powerful it could have killed everyone in the Hart Office Building if it had gotten into the ventilation system and they had not been able to get treatment."
The assessment was given to the senators during a closed meeting by Tennessee Senator Bill Frist. Frist is also a doctor and has been working on the situation here with health officials. Democrats were given the same assessment from other officials.
Several thousand people including 50 senators have offices in the building, which has been closed since the Daschle letter was received.
Officials now say there were 2 grams of anthrax in the letter, enough to contain a billion spores.
Twenty-eight Daschle staffers are still being treated for anthrax exposure and all are said to be doing well.
The news came as the Capitol itself and buildings around it remained barricaded and under heavy guard. With Capitol police now on 12-hour, 6-day-a-week shifts congressiona leaders are seriously discussing bringing in National Guard troops to relieve them. No final decision on that.
As for the Hart Building, the plan now is to seal it and flood it with decontamination gas. The hope is to have it safe and reopened by the middle of next month, but at this point there's no guarantee it can be done.
©MMII CBS Worldwide Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed