Question: Who was claimed to be a suspect in the 2001 anthrax attacks?
About the article "Person of interest", section ""Hatfill v. Ashcroft"".

Candidate passages:
While at Boston College, Guillemin did extensive research on hospital technology and medical ethics, receiving fellowships to work on the U.S. Senate Finance Committee staff and at the Hastings Center for the Study of Ethics.
She was also co-head of the National Library of Medicine's HealthAware Project, a joint project with Harvard Medical School to test how the internet could be used to educate people about preventive health measures.
In 1986, Guillemin became the third wife of the prominent Harvard geneticist and molecular biologist Matthew Meselson.
Meselson was well into a second career as an anti-chemical and biological weapons activist and it was at this time that Guillemin became interested in the misuse of biomedical science by government weapons programs.
She involved herself in two of her husband's investigations of alleged violations of international arms control agreements by the Soviet Union which involved germ weapons.
The first was the "yellow rain" accusation by the United States against the USSR, to the effect that the Soviets enabled the Laotian army to use deadly mycotoxins to attack Hmong refugees allied with the US during the Vietnam War.
This accusation had been disputed by Meselson in 1983 when he argued that the yellow material was actually bee feces mistaken for a biological weapon by those under attack and by certain US government scientists.
(The issue remains disputed and the US government has not withdrawn the allegations, arguing that the controversy has not been fully resolved.
)In 1992, Guillemin became part of Meselson's investigation into another Cold War controversy, the 1979 outbreak of anthrax in Sverdlovsk, a closed Soviet city in the Ural Mountains.
The Soviet government claimed the cause was infected meat.
Guillemin's interviews with the families of victims (64 people were recorded as dying) resulted in an epidemiological map showing the source to be an air-borne release of anthrax spores from a military facility where, in violation of the 1972 Biological Weapons Convention, the testing of anthrax weapons had been in process.
In 1994, the results of this research were published in "Science" and in 1999 her book on this research was published ("Anthrax: The Investigation of a Deadly Outbreak", U of California Press).
After 9/11, with the advent of the anthrax letter attacks, Guillemin was frequently asked by the media to explain the disease, based on her experience in Russia.
In 2005 she published "Biological Weapons: From State-sponsored Programs to Contemporary Bioterorism", Columbia U Press) which offers a concise, comprehensive history of how anthrax and other microbes were developed as weapons over the course of the 20th century, resulting in potential bioterrorism.
She turned her attention to the 2001 anthrax letter attacks after the 2008 suicide of the FBI's prime suspect, an anthrax scientist who worked for the U.S. Army at Fort Detrick, Maryland.
Her third book on biological weapons is about the letters and their impact on victims and government organizations.
It is called "American Anthrax: Fear, Crime, and the Investigation of the Nation's Deadliest Bioterror Attack", (Macmillan/Holt/Times, 2011).  
For six years, the FBI focused its investigation on Steven Hatfill, considering him to be the chief suspect in the attacks.
In March 2008, however, authorities exonerated Hatfill and settled the lawsuit he initiated for $5.8 million.
According to ABC News, some in the FBI considered Ivins a suspect as early as 2002.
FBI Director Robert S. Mueller III changed leadership of the investigation in late 2006, and at that time Ivins became the main focus of the investigation.
The FBI thought Ivins, who had complained about the limits of testing anthrax drugs on animals, might have sent the anthrax letters in order to test a vaccine he had been developing.
After Hatfill was no longer considered a suspect, Ivins began "showing signs of serious strain".
As a result of his changed behavior, he lost access to sensitive areas at his job.
He began being treated for depression and expressed some suicidal thoughts.
On March 19, 2008 police were summoned to Ivins' home in Frederick, MD, found him unconscious and sent him to the hospital.
Late in July 2008, investigators informed Ivins of his impending prosecution for his alleged involvement in the 2001 anthrax attacks that Ivins himself had previously assisted authorities in investigating.
It has been reported that the death penalty would have been sought in the case.
Ivins maintained his security clearance until July 10; he had been publicly critical of the lab's security procedures for several years.
W. Russell Byrne, a colleague who worked in the bacteriology division of the Fort Detrick research facility, said FBI agents "hounded" Ivins by twice raiding his home and that Ivins had been hospitalized for depression earlier in the month.
According to Byrne and local police, Ivins had been removed from his workplace out of fears that he might harm himself or others.
"I think he was just psychologically exhausted by the whole process", Byrne said.
"There are people who you just know are ticking bombs", Byrne said.
"He was not one of them."
However, Tom Ivins, who last spoke to his brother in 1985, said, "It makes sense ... he considered himself like a god".
The "Los Angeles Times" asserted that Ivins stood to profit from the attacks because he was a co-inventor on two patents for a genetically-engineered anthrax vaccine.
The San Francisco-area biotechnology company, VaxGen, licensed the vaccine and won a federal contract valued at $877.5 million to provide the vaccine under the Project Bioshield Act.
However, biological warfare and anthrax vaccine expert Dr. Meryl Nass has expressed skepticism of this purported motive, pointing out that "Historically, government employees do not receive these royalties: the government does.
"On August 6, 2008, a federal prosecutor, U.S. Attorney Jeffrey Taylor, officially made a statement that Ivins was the "sole culprit" in the 2001 anthrax attacks.
Taylor stated that Ivins had submitted false anthrax evidence to throw investigators off of his trail, was unable to adequately explain his late laboratory working hours around the time of the attacks, tried to frame his co-workers, had immunized himself against anthrax in early September 2001, was one of more than 100 people with access to the same strain of anthrax used in the killings, and had used similar language in an email to that in one of the anthrax mailings.
Ivins was also reportedly upset that the anthrax vaccine, that he had spent years helping develop, was being pulled from the market. 
In October 2001, while he was the Senate Majority Leader, Daschle's office received a letter containing anthrax, becoming a target of the 2001 anthrax attacks.
Many of his staffers were confirmed to have been exposed, as well as several of Senator Russ Feingold's staffers and Capitol police officers. 
In addition to attempts to link the anthrax attacks to Iraq, efforts were being made by some to implicate both al-Qaida and another alleged Axis of evil member, North Korea.
Gillan wrote, "Intelligence sources believe that Bin Laden operatives have been preparing for spectacular terrorist strikes using biological weapons for a number of years.
It is believed that viruses causing deadly diseases such as ebola and salmonella were procured in Russia and that anthrax was obtained from North Korea."
Again, the sources were not named.
Letters included in the anthrax-containing envelopes attempted to link the anthrax to international terrorism, but the strain of anthrax used in the 2001 anthrax attacks was khown to be one used within the United States biological warfare program, not one known to be available to countries such as Iraq. 
Letter bombs are usually designed to explode immediately on opening, with the intention of seriously injuring or killing the recipient (who may or may not be the person to whom the bomb was addressed).
A related threat is mail containing unidentified powders or chemicals, as in the 2001 anthrax attacks.