Barbara Hatch Rosenberg, an expert on biological weapons who emerged as a leading voice during the F.B.I.’s rocky effort to identify the culprit in the deadly anthrax attacks of 2001, died on March 14 at her home in Northampton, Mass. She was 97.

Her death was confirmed by her stepdaughter Claudia Kellogg.

A molecular biologist, Dr. Hatch Rosenberg was a founder of the Federation of American Scientists’ Working Group on Biological and Chemical Weapons and a former adviser to the Clinton White House when the anthrax scare startled an America that had recently been wounded by the attacks of Sept. 11, 2001.

Soon after the attacks, envelopes with powder in them were mailed to news outlets, supermarket tabloids and U.S. senators’ offices. The powder was found to contain the spores of the bacteria that causes anthrax, a dangerous infection.

By October, five people had died, including two postal employees at a Washington, D.C., processing center and a 94-year-old widow in Connecticut. Seventeen people were sickened.

Dr. Hatch Rosenberg, a professor at the State University of New York’s Purchase campus, began to develop a theory of the culprit — as an insider, a government scientist or contractor, not a foreign terrorist — that drew the attention of the F.B.I. and many news outlets.

The F.B.I. eventually focused on an American scientist, Steven J. Hatfill, who had once worked at the U.S. Army Medical Research Institute of Infectious Diseases. In August 2002, he was publicly declared a “person of interest” in the investigation by Attorney General John Ashcroft.

But after months of searches, interrogations and hounding by news outlets, Dr. Hatfill turned out to be innocent. In 2008 he won a $5.8 million settlement from the Justice Department and received apologies from media outlets that had suggested he was the culprit.

Dr. Hatch Rosenberg never apologized, and maintained that she had never explicitly named Dr. Hatfill, who later worked in the Trump administrations.

But the F.B.I. agent in charge of the investigation, Van Harp, was later asked in a sworn deposition whether Dr. Hatch Rosenberg had brought up Dr. Hatfill in a meeting she had in June 2002 with the F.B.I. and congressional staffers. Mr. Harp responded, “That’s who she was talking about.”

An F.B.I. search of Dr. Hatfill’s residence was conducted shortly after that meeting, and he later insisted that it was Dr. Hatch Rosenberg who had singled him out.

Dr. Hatch Rosenberg was a dogged opponent of biological weapons and, with the anthrax attacks, her preoccupation had finally reached the public’s consciousness. A week before Sept. 11, she had written an opinion essay in The Baltimore Sun sharply criticizing the George W. Bush administration for rejecting a treaty to monitor compliance with the international Biological Weapons Convention.

Early in November 2001, Dr. Hatch Rosenberg came to the conclusion that the anthrax in the mailings had originated in a government lab at the Army Medical Research Institute of Infectious Diseases, at Fort Detrick, Md. On Nov. 21, she unveiled her suspicions at a meeting in Geneva about the Biological Weapons Convention. The anthrax “came out of the U.S. biological weapons program,” she told the delegates — a bracing hypothesis.

By Nov. 29, the Stockholm International Peace Research Institute was distributing a paper by Dr. Hatch Rosenberg in which she wrote that “the perpetrator is an American microbiologist who has access to recently-weaponized anthrax or to the expertise and materials for making it, in a U.S. government or contractor laboratory.”

The F.B.I. soon came calling, wanting to know if Dr. Hatch Rosenberg had any suspects in mind. Her name began appearing with increasing frequency in news stories. Government scientists called her with tips.

She began criticizing the F.B.I. In a lecture in February 2002 at Princeton, she accused the bureau of “dragging its feet” — perhaps because, she suggested, the suspect might know too much about biodefense secrets.

She “thinks she knows who was responsible for the anthrax attack,” Nicholas Lemann wrote in The New Yorker a month later. The suspect was “confused, upset, depressed, angry,” he quoted her as saying, and had an ax to grind.

Conservative news outlets ridiculed her. The Weekly Standard called her “The Miss Marple of SUNY Purchase” for insisting that the anthrax attacker was American, rather than an Islamist foreigner.

Dr. Hatch Rosenberg persisted, meeting with the F.B.I. in June on Capitol Hill. The F.B.I. began to turn up the heat on Dr. Hatfill, searching his apartment soon after, as “television cameras, satellite TV trucks, overhead helicopters were all swarming around,” he later told reporters.

Barbara Hatch was born in New York City on June 26, 1928, the oldest of three children of Arthur Hatch, who worked for the electric utility holding company Ebasco, and Evelyne (Schreiber) Hatch. She grew up in Great Neck, on Long Island.

She studied chemistry at Cornell, graduating with a bachelor’s degree in biochemistry in 1950, and received a master’s degree in physical chemistry from Columbia in 1957 and a Ph.D. from Cornell in the same subject in 1962.

She worked as a biological chemist at the manufacturing conglomerate American Cyanamid and was a research scientist at Memorial Sloan Kettering Cancer Center in New York from 1962 to 1989. She taught at Cornell (now Weill Cornell) Medical College from 1970 to 1985, before going to Purchase, where she was a research professor of environmental science. She retired in 2008.

Her focus on biological weapons stemmed from her anti-Vietnam War activism in the 1960s and her attendance at the conference in 1986 in Geneva that aimed to strengthen the Biological Weapons Convention, which had been signed in 1972. She was one of the founders of ProMED, the international early warning system now under the aegis of the International Society for Infectious Diseases.

Dr. Hatch Rosenberg was divorced from her first husband, John Rosenberg, in the late 1960s. She married her second husband, the scientist Liebe Cavalieri, in 1970. He died in 2013. She is survived by a brother, C. Richard Hatch; two stepdaughters, Ms. Kellogg and Frances Cavalieri; 11 step-grandchildren and 12 step-great-grandchildren.

In 2007, the F.B.I. began to focus on a government scientist, Bruce E. Ivins, who had access to the anthrax at Fort Detrick — in contrast to Dr. Hatfill, who lacked such access. In July 2008, as the agency closed in, Dr. Ivins died by suicide. Less than two weeks later, Dr. Hatfill was officially exonerated.

But Dr. Hatch Rosenberg continued to criticize the F.B.I. and its investigation; she and several others published a paper in 2011 that raised the prospect that Dr. Ivins had help in obtaining his weapons, or may even have been innocent.

In September 2002, with public anxiety over anthrax waning, Dr. Hatch Rosenberg had despaired that her passion — the threat of biological weapons — was fading from view.

“It is surprising how quickly public terror in response to the anthrax attacks turned to public indifference,” she wrote in The Los Angeles Times that month. “But the story isn’t over. The likelihood of bioterrorism is increasing, and the American public is still the preferred target.”

Representatives from nongovernmental organizations were supposed to sit quietly in the gallery as the delegates to a 4-week conference last summer in Geneva debated how to strengthen the Biological and Toxin Weapons Convention (BTWC) protocol. But that rule didn't stop molecular biologist Barbara Hatch Rosenberg from plopping herself down in a seat on the main floor. "I just walked in; nobody said anything," explains Rosenberg, who serves as chair of the Federation of American Scientists' (FAS's) working group on biological weapons verification. Members of the U.S. delegation were unhappy with the ad hoc seating arrangement, however, and forced her to move back to the gallery. 

Rosenberg's supporters and detractors already knew she was a hard-nosed and vocal activist who's unmovable once she takes a stand. "Barbara obviously makes no bones about her views," says Stephen Morse, an epidemiologist at Columbia University in New York City and a longtime friend. A government scientist who's battled Rosenberg behind tt for years puts a sharper edge on his description of her: "What she brings [to discussions] is an attitude."

That attitude has helped Rosenberg become one of the most visible critics of the FBI's investigation into the anthrax mailings last fall that killed five people and sickened at least 17 others. Less predictably, she also has become the leading nongovernment authority on who might have committed the crimes. Coming soon after the 11 September terrorist attacks, the mailings heightened the country's sense of vulnerability from abroad. But within weeks, Rosenberg asserted in a very public setting that the attacker was an American - specifically, a scientist with access to a federal lab that studies biological agents. The FBI's actions in the case have since converged with that profile, in particular, shining a spotlight on [Steven Jay Hatfill (born 1953)], a microbiologist who earlier this month vehemently proclaimed his innocence and accused the government and the media of ruining his life (Science, 16 August, p. 1109).

How did a 70-something academic - she's an environmental science professor at the State University of New York (SUNY),  Purchase - and bioweapons expert come to take on such a prominent role in this manhunt? Rosenberg professes surprise at the attention she's received, saying simply, "From what I knew the FBI knew, I knew they should be farther along" in their investigation. "That's why I began making statements."

Her motivation, she says, is to deter future assaults by helping solve the first deadly bioweapons attack within the United States. But her profile of the attacker also jibes with other stances she has taken. They include support for a protocol to strengthen the BTWC by advocating inspections to assess bioweapons production-a protocol from which the United States recently walked away (Science, 24 August 2001, p. 1415). She also opposes building more bioweapons labs.

Profiling the attacker. The anthrax letters that struck down and disrupted lives in New York, Florida, New Jersey, Connecticut, and Washington, D.C., last fall embodied the fears of Rosenberg and many other bioweapons experts, who had long warned that the country was ill prepared to handle such an attack. Her 2 decades of work in bioweapons control have given Rosenberg deep ties in the community; almost immediately following the attacks, she began receiving unsolicited tips from U.S. scientists whose connections with federal programs prevented them from speaking publicly.

By early November, Rosenberg says that certain clues, including signs that the anthrax strain had come from the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) at Fort Detrick, Maryland, convinced her that the perpetrator was an American. She went public with those thoughts on 21 November (2001) at a BTWC meeting in Geneva, asserting that New York City "has just been attacked, first by foreign terrorists, then by an American using a weaponized biological agent."

Rosenberg declines to explain why she chose that venue. But her voice rises in anger when she recalls how U.S. officials refused to join with other delegations at the November meeting. "[The U.S. was] accusing everyone else of having bioweapons, when the attack was coming from our program. ... I felt that it was necessary to point out."

Rosenberg came to believe that the scientist-perpetrator didn't intend to kill - after all, she says, the attacker warned that the letters contained anthrax or that the recipients should take penicillin-but rather nursed a grievance against the government for unfairly neglecting the U.S. bioweapons program. Since November, her theories have been widely disseminated over the Internet and in the media.

Earlier this year, Rosenberg wrote that the FBI had a suspect in mind but was reluctant to pursue him because "the suspect knows too much and must be controlled forever from the moment of arrest." She has since grown more circumspect about a possible conspiracy, saying, "I can only speculate as to why" the FBI hadn't been more aggressive.

That view still doesn't sit well with some scientists, although few are willing to criticize her in public. "My feeling is that if there is such a conspiracy, the FBI is not a part of it," says Steven Block, a biophysicist at Stanford University who has advised the U.S. government on bioweapons. Some scientists also felt that it wasn't a coincidence that Rosenberg's profile of the attacker fit one person. "She just seems to be too anxious to pin this on [Hatfill]," says [Dr. Peter B. Jahrling (born 1946)], a senior USAMRIID researcher, who says Rosenberg's comments about the case led him to decide early on that she had Hatfill in mind. Rosenberg maintains that she never named Hatfill or anyone else in comments to 2 the FBI or in her statements.

Rosenberg zealously preserves the anonymity of her sources, saying only that they are government scientists and other insiders. Those within and outside government labs agree that her sources seem knowledgeable. Jahrling, however, suggests that Rosenberg, doesn't have many friends in the government's biodefense labs because she opposes their planned expansion. Any expansion, she has argued, just adds to the pool of scientists with the means to pull off another bioweapons attack.

Both admirers and detractors agree thats he has pushed the FBI forward. "Without question, she's influenced this investigation," says Block, who also strongly suspects that the culprit, if not a U.S. citizen himself, has ties to the U.S. bioweapons program. Privately, scientists who support Rosenberg praise her for taking NEWS FOCUS on what they call a thankless job.

Rosenberg, whom the conservative Weekly Standard ridiculed as "the Miss Marple of SUNY/Purchase" in a recent article, maintains that the importance of finding out who sent the anthrax-tainted letters demanded her involvement and that her celebrity is purely accidental. Mark Wheelis, a microbiologist at the University of California, Davis, and a member of the FAS working group that Rosenberg runs, agrees that she generally shuns the limelight. But her determination, he notes, serves her well here: "The toughness is not part of her normal manner; it's a reserve she can draw on when it's called for."

And what if she's wrong? Rosenberg concedes that interrogating Hatfill might not help the FBI crack the case. But she quickly reverts to character. Even if that's true, she says, "the broad principles and the things I've said, I stand behind." 

The man the FBI has fingered as a subject in its ongoing investigation of the anthrax killings, bio-weapons researcher [Steven Jay Hatfill (born 1953)], unloaded on his critics last week during a press conference aimed at clearing his name. He accused John Ashcroft of violating the Ten Commandments, the New York Times of violating journalistic ethics, and a New York scientist of spearheading a vendetta against him. 

The scientist Hatfill named was Barbara Hatch Rosenberg, a biological arms control expert at the State University of New York at Purchase and chairwoman of the Federation of American Scientists' Chemical and Biological Arms Control Program. For months, Rosenberg has been quoted widely on all things anthrax. Her memos, which were first published on the FAS Web site back in January, have served as both laboratory and road map for theories about who is responsible for the anthrax attacks. 

Rosenberg says her memos began as an effort to pressure the FBI, which she has repeatedly accused of dropping the ball in its investigation. "I began just putting together the data that was available, and discussing it on this e-mail list. Then people starting sending me information, so I sort of became a center for collecting information on the subject," she says. 

While there is anything but consensus about Rosenberg's controversial theories, they clearly have informed much of the media speculation about the anthrax killer -- speculation that has thrust Hatfill's name into the headlines. 

But Rosenberg tells Salon she was always very careful never to name Hatfill, despite requests from everyone from the FBI to the media to the U.S. Senate. "If there isn't a good reason for what they're doing, I think it's really disgusting that the FBI's done this," Rosenberg says, joining Hatfill's critique of the bureau. "No question, it was the FBI who outed him. They informed the media before they searched his apartment [in June] so that the media would be there in their helicopters, etc. The FBI clearly did this on purpose." 

Rosenberg acknowledges the FBI decision may have come after her visit to the U.S. Senate increased the pressure on the bureau to show it was making progress in the case. Whether intentional or not, the FBI search allowed media outlets an excuse to print much of the speculation that had been circling around Hatfill for months. Much of that speculation was rooted in, or at least fed by, Rosenberg's memos, many of which never found their way to the FAS Web site. 

For the last year, a listserv, run through the Stolkholm International Peace Research Institute, has been a place where bio-weapons experts and journalists lurk to share theories on, among other things, the anthrax killer. Some of the theories that have been voiced on the SIPRI listserv have found their way into media reports. Others have not. There has been, for instance, much information and speculation about Hatfill himself, and the FBI's investigation of Hatfill, that has not appeared in media accounts. Conspiracy theories about the U.S. government are popular, too -- that the anthrax attacks somehow were a CIA test to see how Americans respond to a biological weapons attack, or an effort to get more funding for bio-weapons research. Other discussions focus on Iraq as the possible source of the anthrax. 

Rosenberg admits some of the information in her first anthrax memo has been disproved, and that her profile of the killer has changed over the last several months. "I think I've been able to refine some of my ideas. Some of them maybe were based on scanty information," she says. "All along, there's been speculation involved in all this. But I think that there's been more information that's become available over time, and I've been able to refine my ideas." 

But she says she's been careful not to conduct a public lynching. Rosenberg says that when she feared her speculation about the anthrax killer might implicate a particular individual, she opted not to post the memos on the FAS site. Instead, they were sent to the listserv. In reference to a June memo, she says: "I put it on an e-mail discussion group, but I decided I did not want to put it on the [FAS] site because it got a little too specific, although it didn't mention any names." 

In that June 13 memo, for example, Rosenberg describes a suspect who has "the right skills, experience with anthrax, up-to-date anthrax vaccination, forensic training and access to USAMRIID and its biological agents." The suspect's job, she said, was to devise bio-terror scenarios. He had had a recent job setback. And though Rosenberg indicated in the memo that the description might fit up to 10 different people, bio-defense experts, journalists and others who followed the case closely could have concluded that she was referring to Hatfill. 

And even though she didn't post the memo, it has still been posted other places.

Since emerging as a major critic of the FBI's investigation of the anthrax case, Rosenberg herself has come under fire. She has been deemed a home-wrecker by Hatfill, and a left-wing loony by conservative publications like the Weekly Standard and the Wall Street Journal's editorial page. The Standard, which has long made the case that the anthrax came from Iraq or al-Qaida, ridiculed her "sensational pronouncements" and "surprisingly unscientific, even Oliver Stone-scale, incaution about the 'facts' at her disposal." To support her theories, the Standard wrote, she jumped to unwarranted conclusions about the chemistry of anthrax production and about the U.S. government's sinister motives in botching the investigation. 

Her colleagues say many of the criticisms against Rosenberg have been unfair, and insist she has an impeccable reputation in the scientific community. "She is a sound lady. They may not like her in Washington, but she doesn't believe in flying saucers or anything like that," says Martin Hugh-Jones, a professor at Louisiana State University and one of the nation's leading anthrax experts. 

But while she may not be a kook, she does have a long history as an activist. And that, her supporters say, is why she's become a foil for Hatfill, and for conservative media outlets who have derided both Rosenberg and her theories. 

Rosenberg says her interest in biological weapons grew out of her activism as an advocate for nuclear arms control in the 1970s and '80s. "At first, I was concerned about nuclear weapons. Then being a biologist, I learned about biological weapons," she says. In the 1990s, "I realized the U.S. hadn't passed implementing legislation for the Biological Weapons Convention, so I decided to work on that, and lobbied very hard for it." 

But she lost. And when the Bush administration last year backed away from the treaty,Rosenberg penned an Op-Ed piece in the Baltimore Sun. "Rejection of the biological weapons treaty follows an administration pattern of arrogance in conducting foreign policy that seems almost designed to create antagonism," she wrote. 

But Bush's decision was hailed by the conservative press. The Washington Times ran an editorial of its own with the headline "Bush Was Right to Reject Biological Weapons Protocol." The Wall Street Journal also expressed support for the move. 

Some say this political history is part of what's motivating the current criticism of Rosenberg in conservative circles. University of Maryland professor Milton Leitenberg, who serves on the same FAS committee as Rosenberg, said his colleague is "a useful foil" for conservative attacks. 

The Journal has been among the biggest Rosenberg critics. A recent column by Robert Bartley begins with a synopsis of the liberal history of the FAS, and claims Rosenberg is on a crusade against Hatfill. 

"So the full agenda is to prove that Dr. Hatfill concocted his anthrax with the help of leading bioweapons scientists and in intelligence facilities," Bartley writes. "That is, that these secret facilities have been used to violate the Biological Weapons Convention." 

Rosenberg has critics in the scientific community as well. Among them are David Franz, former commander of the U.S. Army Medical Research Institute of Infectious Diseases, and former U.N. biological weapons inspector to Iraq. 

Former UNSCOM bio-weapons inspector Dick Spertzel also disagrees with Rosenberg's assertion that the anthrax came from a U.S. scientist who probably has CIA ties. Spertzel has maintained the anthrax originated in Iraq, and recently defended Hatfill, saying the biologist "is being crucified." 

But Franz and Spertzel are implicated in Rosenberg's June memo about the motivation of the person she believes to be the anthrax killer. And in the theory, there are hints of Rosenberg's liberal political roots. "The suspect is part of a clique that includes high-level former USAMRIID scientists and high-level former FBI officials," Rosenberg writes. "Some of these people may wish to conceal any suspicions they may have about the identity of the perpetrator, in order to protect programs and sensitive information. This group very likely agreed with David Franz, former Commander of USAMRIID, when he said: 'I think a lot of good has come from it [the anthrax attacks]. From a biological or a medical standpoint, we've now five people who have died, but we've put about $6 billion in our budget into defending against bioterrorism'." 

Rosenberg says she laments the public scrutiny Hatfill has come under if he is in fact not guilty. But, she says, her efforts to prod the FBI were born out of frustration that the bureau's lackluster investigation would pave the way for future bio-terror attacks. 

"I do think that apprehending the perpetrator of the attacks as fast as possible is a way of deterring future bio-terror attacks," she says. "I think the failure to do so has now opened up the possibility for future attacks in a way that was very unlikely before." 

John Payne Woodall — known to all as Jack — was one of the founders of ProMED, an internet-based outbreak reporting system run under the auspices of the International Society for Infectious Diseases. The acronym is short for the Program for Monitoring Emerging Diseases.

ProMED was established in 1994. Woodall, who was 81 at the time of his death on Monday, was involved virtually until the end, contributing frequently to discussions about a dangerous yellow fever outbreak in Angola and the Democratic Republic of Congo.

The unprecedented size of the outbreak has strained supplies of yellow fever vaccine at points this year and Woodall feared the need would outstrip the supply.

He pushed tenaciously for the World Health Organization to recommend use of a fractional dose of vaccine, an approach the organization endorsed in June.

In urgent emails to like-minded scientists and others he thought could influence the cause, Woodall would often sign off with a quote from the cartoon strip “Calvin and Hobbes.”

He described the quote as his motto: “God put me on this earth to accomplish a certain number of things. Right now I’m so far behind I will never die.”

The list of Woodall’s accomplishments was long, friends and colleagues said.

An arbovirologist, Woodall was involved in some of the earliest research on the Zika virus, which was discovered in Uganda in 1947.

He was not involved in the virus’s discovery — he was still a boy at that time — but reported on finding it in mosquitoes in Uganda, where he worked for a time after graduating with a doctorate in entomology and virology at the London School of Hygiene and Tropical Medicine.

His life and career took him literally around the globe. He spent part of his childhood in China, noted Dr. Marjorie Pollack, a friend and fellow ProMED moderator. And as a scientist, he worked at the Rockefeller Foundation in New York, the Belem Virus Laboratory in Brazil, the Yale University arbovirus research unit in New Haven, Conn., and the New York State Health Department.

Pollack met Woodall in 1977 when he was director of the Centers for Disease Control and Prevention’s dengue branch, in San Juan. Later, Woodall spent 14 years at the WHO in Geneva.

Pollack described him as “a delight.”

“He had an inquisitive mind, a brilliant mind, and he would stimulate discussion wherever he was,” she recalled.

“He sometimes would come across professionally as a bull in a china shop if he felt that things that were going on were wrong. … But that was part of his charm.”

Dr. Stephen Morse, a professor of infectious diseases at Colombia University, was one of the other cofounders of ProMED. (The third was Barbara Hatch Rosenberg, a molecular biologist.)

“Jack had a remarkable life and did so many things, I once jokingly referred to him as our own Indiana Jones,” Morse said.

In the late 1980s and early 1990s, growing concern about the potential use of biological agents in warfare and the risks posed by emerging diseases led to calls for improved surveillance.

In the nascent days of the public internet, that wasn’t necessarily easy to do, Morse said. But Woodall was keen on the capacity of technology to connect people in public health.

ProMED evolved to become an invaluable early warning system, alerting the world of unusual disease activity in southern China that would later become the 2003 SARS outbreak.

“Jack really believed in emerging infectious diseases and fixing the disease surveillance problems, the challenges to find out about outbreaks sooner,” Pollack said.

Dr. Lawrence Madoff, the editor of ProMED, described Woodall as a character. “He clearly spoke his mind. He definitely was the ‘speak truth to power’ type,” he said.

That said, Woodall insisted ProMED should not criticize governments for their handling of outbreaks, Madoff said, noting he felt it was more important to engage governments to encourage transparency than to play an adversarial role.

Woodall died in London following a battle with pancreatic cancer.