MARGARET WARNER: And for the latest, we turn to Scott Shane. He's covering the story for the New York Times.
Scott, thanks for being with us. How close is the government now to letting the public know what it knows about Bruce Ivins and whether, in fact, he is the anthrax killer?
SCOTT SHANE, New York Times: We don't know for sure. We know that they're working on getting grand jury secrecy lifted from the investigation, declaring the investigation closed, and getting a judge to essentially give permission to make information that's been secret public.
They're talking about possibly doing it as early as Wednesday, but no time has been set. In the meantime, they're contacting the family members of those five people who died of the anthrax and the 17 survivors, because Robert Mueller, the FBI director, has promised to brief them before the public gets the information.
MARGARET WARNER: Now, what have we -- what have you learned in the past few days, since the story broke, about why the FBI has zeroed in on Ivins, in particular, and how long he's been the special focus?
SCOTT SHANE: Well, the anthrax investigation has been going on, of course, for almost seven years. And at the very beginning, the FBI, by its own admission, was fairly clueless about what they now call microbial forensics, the idea of using the genetic and other attributes of the bacteria to trace it back to a source.
But they've developed a lot of science over the first few years of the investigation. And certainly, by about 2005, they had been able to track the anthrax to Fort Detrick, the Army's lab in Frederick, Maryland.
Now, at that point, they had a supply of anthrax they could match to the letters, but quite a number of people had access to the lab. I'm told that about 10 people used it regularly, and perhaps several times that number had passed through it at various times.
So the FBI then began the painstaking process of trying to eliminate the people who'd worked in that lab.
About a year-and-a-half ago, they began to focus intensively on Bruce Ivins. This was partly because they had eased up on a focus that had lasted for two or three years on Steven Hatfill, another scientists at the Fort Detrick Lab, who had worked there from '97 to '99. Dr. Ivins continued to work at the lab up until his suicide last week.
The FBI kept him under surveillance, followed him around in vans for at least a year. They interviewed his family, his colleagues. And they have convinced themselves that he was the anthrax mailer.
Now, having focused so intensely on Dr. Hatfill and then, just in June, having paid Dr. Hatfill about $5 million after deciding it wasn't he who had mailed the anthrax spores, there's certainly reason to be cautious in pinning that biological attack on Dr. Ivins, who's no longer around to defend himself.