WASHINGTON -LRB- CNN -RRB- -- Federal investigators will declare the 2001 anthrax case solved on Wednesday , when they make public their case against government researcher Bruce Ivins , a government source familiar with the case told CNN on Tuesday . Ex-Army scientist Bruce Ivins , seen here in 2003 , died from an apparent suicide last week . But the case will not be considered closed , because administrative details remain incomplete , said the source , who spoke on condition of anonymity because the investigation is ongoing . Before making the information public , the FBI is expected to share the evidence of Ivins ' involvement with survivors and relatives of victims in the anthrax attacks , the source said . A lawyer for Maureen Stevens , the widow of Bob Stevens , the first victim of the 2001 attacks , said she was invited to the session and will attend . The tabloid photo editor died after inhaling anthrax that investigators believe was in a letter sent to American Media Inc. , the publisher of the Sun and National Enquirer tabloids , at its offices in Boca Raton , Florida . Another source familiar with the investigation said Tuesday that in the fall of 2001 , Ivins borrowed a machine that can convert wet anthrax , the kind used at Fort Detrick , into dry powder , which was found in the anthrax letters . Such machines , called lyophilizers , are not usually used at Fort Detrick , where Ivins worked , though they are easy to obtain . Experts said the report may have no significance . `` I would n't necessarily make the conclusion that , just because he had access to a lyophilizer and used a lyophilizer , that that provides a smoking gun , that he must be using this for sinister purposes , '' said Peter Hotez , chairman of microbiology at George Washington University in Washington . Richard Spertzel , a former biodefense scientist who worked with Ivins at the lab at Fort Detrick , said there was `` no way '' a lyophilizer could have created the fine anthrax spores used in the 2001 letters . Spertzel said a more advanced machine would have been needed , and that no one working at a U.S. government lab could have produced such high quality anthrax in secret . Ivins , who is expected to be blamed for the mailings of the toxin , which killed five people and sickened more than a dozen others -- died July 27 at a hospital in Frederick , Maryland , from an apparent suicide attempt two days earlier . No charges have been made public . He became a suspect after investigators found DNA evidence from the 2001 anthrax mailings on a flask used in his laboratory at the U.S. Army Medical Institute of Infectious Diseases , said a source who is familiar with the investigation but not authorized to speak publicly about the case . Ivins had worked for decades in the biodefense lab at Fort Detrick , where he was trying to develop a better vaccine against the toxin . The FBI had traced the anthrax used in the attacks to the lab by using a new technology , a U.S. official familiar with the investigation said . Authorities were looking at whether Ivins may have released anthrax to test a vaccine he was working on , another official said . Some of the anthrax-laced letters , written in crude block letters , included the words , `` Take penacilin -LRB- sic -RRB- now , '' according to photographs released by the FBI . Since Ivins ' death , suspicions about his involvement in the anthrax attacks have surfaced alongside questions about his sanity . At the time of his death , the 62-year-old scientist was under a temporary restraining order sought by a social worker who had counseled him in private and group sessions . She accused him of having harassed , stalked and threatened her with violence . The woman told the court in her complaint that Ivins had been treated at a mental health facility . Steven Hatfill , another government scientist who was named by the Justice Department as a `` person of interest '' in the attacks , was never charged . He sued the department , which settled the case in June . The skepticism in scientific circles about the strength of the case against Ivins heightens the importance of the government 's unveiling of its evidence against the scientist , a former prosecutor said . `` I think the public and the survivors of the anthrax attacks are entitled to see the evidence before the grand jury , '' said Andrew McBride . `` And if there was a draft indictment and they were ready to indict Mr. Ivins , they ought to see that as well . '' CNN Producer Kevin Bohn contributed to this story .