The FBI botched an analysis of anthrax evidence that linked an Army researcher to the deadly letters that killed five people in the days after the Sept. 11 terrorist attacks, according to a panel of scientists.

The 190-page report, released Tuesday by the National Research Council, says the anthrax in the mailings can’t be definitively linked to anthrax found in the lab of Bruce Ivins, a researcher at the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick in Frederick County. Ivins committed suicide in 2008 as prosecutors were preparing to indict him.