Enlarge By Nicholas Kamm, AFP/Getty Images U.S. Attorney Jeffrey Taylor outlines the case against Bruce Ivins Wednesday at a news conference. JUSTICE DEPARTMENT'S ANTHRAX COURT DOCUMENTS JUSTICE DEPARTMENT'S ANTHRAX COURT DOCUMENTS Part One, (PDF file, 11.8 MB) Part Two (PDF file, 10.3 MB) Part Three (PDF file, 7.1 MB) Part Four (PDF file, 5.7 MB) Part Five (PDF file, 3.4 MB) Part Six (PDF file, 2.1 MB) LEARN MORE ABOUT ANTHRAX LEARN MORE ABOUT ANTHRAX MULTIMEDIA: Information from the National Institutes of Health WORLD HEALTH ORG.: Fact sheet FDA: Update on potential anthrax vaccine CDC: Anthrax backgrounder WASHINGTON  On several nights before the anthrax attacks in September and October 2001, bioweapons scientist Bruce Ivins repeatedly spent long periods alone in a secure laboratory that housed a strain of the lethal bacteria. He later "could provide no legitimate reason" for his after-hours work to investigators, who used new DNA technology to match the specific strain of spores in Ivins' lab with the one used in the attacks. Those were among the revelations contained in court documents unsealed Wednesday, as the U.S. government proclaimed it had solved the nation's worst case of bioterrorism. The anthrax attacks, which involved mailings of powdered spores that killed five people and sickened at least 17 others, jolted a country reeling from the Sept. 11 attacks and have been a major mystery of the post-9/11 period. The release of the court documents and the government briefing that followed shed light on the evidence against Ivins, 62, who died July 29 from an overdose of acetaminophen. Yet they also raised new questions about the government's handling of the seven-year anthrax probe, which initially focused on another scientist and turned toward Ivins less than two years ago. TIMELINE: Key dates in probe "We are confident, based on the evidence we had, that we could prove this case beyond a reasonable doubt," said Jeffrey Taylor, U.S. Attorney for the District of Columbia. "We are confident that Dr. Ivins was the only person responsible for these attacks." The government's assertion was disputed by Ivins' lawyers, who issued a statement calling the Justice Department briefing an "orchestrated dance of carefully worded statements, heaps of innuendo and a staggering lack of real evidence — all contorted to create the illusion of guilt by Dr. Ivins." Much of the evidence against Ivins is circumstantial, including an e-mail he sent to an associate after the 9/11 terror attacks that contained warnings about terrorists having "anthrax and sarin gas," and having "decreed death to all Jews and Americans. There was similar language in the letters that were mailed with the deadly powder. The court papers released Wednesday also alleged that Ivins, when asked to provide samples of certain anthrax spores for testing by investigators, tried to mislead agents by providing other types of spores — and then lied about doing so. The documents also describe increasingly erratic and threatening behavior by Ivins as federal agents pressured him for details. Taylor and others noted that such circumstantial evidence is routinely used to win convictions in U.S. courts, but some legal analysts found the government's case against Ivins lacking. They noted that beyond matching the spores used in the attacks to those "created and solely maintained" by Ivins at the U.S. lab at Fort Detrick in Frederick, Md., the documents cited no physical evidence — no hair or handwriting match, for example. "If they're saying, 'We found the guy, and this is it,' to me this falls short of that mark," said Michael Greenberger of the Center for Health and Homeland Security at the University of Maryland School of Law. "There's a lot of circumstantial evidence that certainly supports probable cause, but I have questions (about) whether this proves anything beyond a reasonable doubt." Some scientists, however, saw the link between the specific type of spores used in the attacks to Ivins' lab as particularly strong. In early 2005, using new techniques, FBI scientists identified the "genetically unique" parent used in the anthrax mailings. Eight of the lab samples the FBI collected had four genetic mutations unique to the anthrax mailings, an affidavit says. All came from a single flask, called "RMR-1029," that Ivins created and maintained at the Fort Detrick lab. The affidavit says Ivins was the "sole custodian" of the flask since its anthrax was first grown in 1997. "We have a flask that's effectively the murder weapon, from which those spores were taken, that was controlled by Dr. Ivins," Taylor said, adding that others with potential access to the flask gradually were ruled out as suspects starting in 2005. "The anthrax in that flask was created by Dr. Ivins." Steven Salzberg, a University of Maryland biologist, says that "finding those four mutations, that's pretty compelling evidence." Salzberg was an author of the 2002 Science magazine paper that first released genetic details of the anthrax in the 2001 bioterrorist letters. "If Bruce Ivins has been the 'sole custodian' — if that's true — then they got him," Salzberg said. On Capitol Hill, where several buildings had to be shut down after anthrax-laced letters were sent to then-senator Tom Daschle and Sen. Patrick Leahy in 2001, the Justice Department's briefing drew some skepticism. U.S. Rep. Rush Holt, D-N.J., whose district includes a mailbox that was used to send the letters containing anthrax, said that "while the circumstantial evidence pointing to Dr. Ivins … is compelling, a number of important questions remain unanswered, such as why investigators remained focused on Dr. (Steven) Hatfill long after they had begun to suspect Dr. Ivins … and why investigators are so certain that Ivins acted alone." The case against Ivins When tainted letters began arriving at news organizations and the Senate offices in mid-September 2001, the FBI initially focused on foreign terrorists. Then investigators began to suspect Hatfill, another Fort Detrick weapons scientist, whom then-attorney general John Ashcroft called "a person of interest" in the case. Hatfill was subjected to 24-hour surveillance. The FBI wiretapped his phone and accosted him at job interviews, according to a lawsuit he later filed that accused the government of invading his privacy and ruining his career. In June, Hatfill won a $5.82 million settlement in the case. On Wednesday, Taylor said the government began to consider Ivins as the primary suspect last year. "We thoroughly investigated every other person who could have had access" to the key flask of anthrax at the Fort Detrick lab, "and we were able to rule out all but Dr. Ivins," Taylor said. The probe found that Ivins had access to a sophisticated machine that could have been used to dry the anthrax spores to make them airborne. In the days before each of the 2001 anthrax mailings, Ivins worked at the lab unusually late into the night and on weekends in the high-security section where the anthrax is stored, the probe found. When questioned by FBI agents, he said he was having trouble at home, the documents say. A few days before the attacks began, the government says, Ivins sent the e-mail that used language similar to that of the anthrax letters. Among the other evidence outlined Wednesday: •Envelopes used in the mailings were available in only a few places, including the Frederick, Md., post office frequented by Ivins. •The court documents cited e-mails in which he acknowledged being paranoid and depressed and said he was obsessed with a sorority that has an office near the Princeton, N.J., mailbox used to send some of the anthrax letters. Eventually, the FBI began watching Ivins day and night. He showed "consciousness of guilt," Taylor said. Ivins also told people at his group therapy session that he wanted to kill those who had wronged him, Taylor said. That was on July 9, according an affidavit. Ivins told the social worker and group members that he was a suspect in the anthrax investigation. "He stated … he was angry at investigators, the government and the system in general. He said he was not going to face the death penalty, (and) had a plan to kill co-workers and other individuals," the document says. "He said he had a bulletproof vest and a list of co-workers and … was going to obtain a Glock firearm from his son within the next day because federal agents are watching him and he could not obtain a weapon on his own." The social worker called the Frederick police, who took him into custody and sent him to a hospital for evaluation. He was later released. 'He did some stupid things' Evidence of a potential motive for Ivins to have sent the letters is scant. Investigators have pointed to trouble at work with a failing anthrax vaccine and a possible cut in his program. The FBI has not said how agents eliminated as suspects others in the lab who also may have had access to Ivins' flask. The FBI also did not explain why it relied on Ivins to assist their probe even after the 2003 incident in which Ivins gave investigators unsuitable anthrax samples from his lab. And agents have not been able to place Ivins at the Princeton mailbox where the anthrax letters were mailed, but they say he had the time in his work and home schedules to drive there the days the letters were mailed. One of the nation's leading anthrax researchers, Martin Hugh-Jones of Louisiana State University, says the documents leave some critical questions unanswered. For example, they fail to confirm a genetic match between the strain of anthrax found in Ivins' laboratory and the first victim, Robert Stevens of American Media in Boca Raton, Fla. "The evidence points at Ivins, but they don't give evidence excluding other people working in the same facility," Hugh-Jones says, adding, "Bruce didn't help himself. He did some very stupid things." Geneticist Michael Stebbins of the Federation of American Scientists in Washington, D.C., notes that the science is not very detailed in the affidavit, which the government prepared to obtain approval for a search warrant — not to present its case to a jury. "The four mutations, that alone isn't a smoking gun, but it certainly is compelling evidence that the anthrax came from the flask where Ivins worked," he says. Holt, who was briefed Wednesday by FBI Director Robert Mueller, says, "I hope that as the rest of the information comes out, it will seem more than just another assertion by the FBI that they've got the right guy." 'No doubt in my mind' Victims of the anthrax attacks and family members of those who died reacted emotionally at a private briefing by Mueller, said Patrick O'Donnell, a New Jersey postal worker who was infected by the anthrax. It lasted nearly four hours and included every agent assigned to the case. "A lot of people were breaking up, crying," O'Donnell said. He found the evidence circumstantial, but solid. "I pretty much have no doubt in my mind he did it now," he said. However, he wishes Ivins were alive to stand trial. "It left a lot of doors open." Ivins' attorney, Paul Kemp, attended a memorial service for Ivins on Wednesday at Fort Detrick. "I don't understand how 250 scientists and soldiers, including the base commander and the commanding general, could be here eulogizing Bruce and the FBI seriously consider him a suspect," Kemp said via e-mail. "In the words of his commander, he was open, sharing, funny and scientifically brilliant." Taylor, though, said the Justice Department is in the process of ending its investigation and plans to formally close the case. "We regret that we will not have the opportunity to present the evidence to a jury," he said. Contributing: Marisol Bello and Rebecca Kaplan Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. 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