At a laboratory in northern Arizona, microbiologist Paul Keim toiled over the pedigree of the anthrax spores that killed three people and shook the U.S. capital to its roots.
At Ft. Detrick, Md., Army germ warfare specialists struggled with another question: whether the toxic white powder had been chemically altered to be more deadly.
At the FBI, officials admitted that they lacked vital expertise, despite millions of dollars spent on a new crime lab and special units for hazardous materials and weapons of mass destruction.
"We certainly didn't go out and hire one or several experts in biological weaponry," a senior federal law enforcement official said. "I'm afraid the public has the right to expect that we would have that kind of expertise, and we don't."
Now, as it enters its fourth week, the massive but fragmented anthrax investigation has entered a frustrating phase. Despite an all-out effort, progress has been so slow that it's impossible to tell which will come next: breakthrough or stalemate.
Several thousand FBI agents are wading through a swamp of leads, for example, but most of them prove to be false. Scores of forensic experts are studying scientific clues, but the tests take precious time and may never lead to the perpetrators.
And the effort is hampered by confusing and often contradictory statements from officials.
As sobering as all this is, it may be spawning a larger problem:
The outbreak of anthrax terrorism along the East Coast has exposed significant weaknesses in institutions that Americans long have considered to be the most dependable in the world. U.S. medical science, public health and political leadership all have been found wanting in one aspect or another.
But perhaps no shortcomings have proved more fundamental--and had greater repercussions around the country--than those of law enforcement. That someone has contaminated the mail with anthrax is bad enough. That investigators seem stumped makes it far worse.
"The unknown is the weapon with anthrax, not the anthrax itself," said Jay Segal, a specialist in emotional trauma at Temple University's Center for Public Health in Pennsylvania. "As Americans, we like to have answers, certainty. The unknown is killing us.
"It's not that anthrax is in our mailboxes. It's that it's in our minds."
"There is a feeling that government is not in control," said Ray Kelly, former director of the U.S. Customs Service and now chief of security for Bear Stearns in New York. "There is no indication we know where this is coming from or that law enforcement is hot on the trail of anybody.
"We always thought we were protected, especially in the medical field, and that leaders knew what to do. Not this time."
Even an FBI official involved in the inquiry conceded that the halting pace of the investigation is beginning to strain the public.
"We need to make an arrest soon," the official said, speaking on condition of anonymity, "because the anxiety level out there needs to be ratcheted down."
More Resources, but Expertise Lags
For years, according to one senior federal law enforcement official with scientific expertise, the FBI has been asking for more resources to combat bioterrorism, along with a budgetary wish list of other needs. Beginning in 1996, after high-profile bioterrorism incidents in Japan and elsewhere, the FBI received millions of dollars to do just that.
But there are gaps in the FBI's capabilities. "In terms of knowing the finer details of the [anthrax] materials, we don't have the kind of experts--biological experts--that we have for, let's say, fingerprinting and inks," the official said.
"It is a very small pool of experts, but they are not ours. We are essentially having to hire them, or they are coming from other government agencies."
In the weeks since the anthrax letters began arriving, the FBI has turned to experts at the CIA and the Defense Department. This outside expertise is available, but using it requires speed and coordination that goes well beyond the norm.
One result has been that, as the public poses urgent questions, the nation's lead law enforcement agency has been slow to respond with answers or even relevant information.
"I can't blame them for being concerned," the official said. Anthrax contamination, he said, "really hits home."
Many of the anthrax samples have been sent for testing to the Centers for Disease Control and Prevention in Atlanta. Others are being reviewed at Ft. Detrick by the U.S. Army Medical Research Institute for Infectious Diseases, known as USAMRIID.
But much of the most arcane scientific gumshoe work has been farmed out to labs outside the government, including the one headed by Keim at Northern Arizona University in Flagstaff.
Keim has spent much of his professional life trying to learn more than anyone else in the world about one tiny subject. He has collected samples of anthrax spores from around the world, patiently studying and cataloging each one.
Today, Keim's collection, which neither the CDC nor USAMRIID can match, amounts to a fingerprint bank of the nearly 1,000 strains of the bacterium known to exist.
Keim's analyses already have enabled authorities to tell the world that anthrax spores found in Florida, New York and Washington are similar, perhaps from the same strains. That could help authorities determine who mailed the tainted letters and whether the same person or group was responsible for all of them.
What Keim has done so far was the quick, easy part. As he delves deeper, trying to determine whether the strains are identical and what that might reveal about their origin, the rate of progress has slowed.
The tests take time, and they cannot be hurried.
Moreover, it is by no means certain that the results will point toward specific individuals or groups, much less reveal where they are now. Officials working on the anthrax probe are haunted by memories of the Unabomber case, in which investigators accumulated mountains of scientific and other evidence but found the bomber himself only after his brother turned him in.
As Keim plows ahead, specialists from the intelligence and defense communities are working at facilities across the country. They are focusing on how the anthrax was processed, whether it comes from sophisticated processes known to only a few state-sponsored labs or from more elementary procedures that could have been performed by almost any microbiologist--or even by someone with less training.
Out on the street, meantime, where the old-fashioned shoe-leather work is done, federal agents have encountered unavoidable but maddening delays.
Although about 7,000 FBI staff members, one-fourth of the agency's work force, has been assigned to the anthrax investigation, much of their time and energy has been spent on responding to anthrax scares, most of them unfounded.
"The system got completely overloaded with the suspicious packages, letters and envelopes," one law enforcement official said. "And then, more recently, we have gotten hundreds of deliberate hoaxes, many of them to reproductive rights clinics."
Distracted by these alarms, agents have been slow to complete tasks directly related to the anthrax attacks. What forces the FBI to deal with the daily alarms and diversions is another hole in the system exposed by the crisis: With some exceptions, local authorities are completely unequipped to deal with possible biological hazards.
"In spite of all the training and the talk of the last few years about crisis response to bioterrorist threats, the fact of the matter is that protective clothing and gear are glaringly lacking," an FBI official said, on condition that his name not be used because of his position.
Masks, gloves and other essential protective gear are in short supply. So is the capability to scan for toxins, safely collect samples and decontaminate sites.
And with most alarms proving to be false, the FBI's hazardous material unit recently warned field agents to do a thorough hazardous material analysis before taking any substance into the laboratory.
The obstacles and diversions have slowed the investigation, and the outcome remains in doubt. But a vast effort backed by enormous resources still is proceeding on many fronts, from retracing postal routes and analyzing handwriting samples to pursuing leads and gathering intelligence in cooperation with friendly governments around the world.
"There's a lot going on in this investigation that we're just not telling people about," one FBI official said. "Our agents are very active around the country, and we're being very aggressive."
Times staff writers Eric Lichtblau and Jack Nelson in Washington contributed to this report.