The FBI contacted Sandia after 5 people died and others were hospitalized during anthrax attacks in 2001 involving letters containing bacillus anthracis bacterium sent to the press and to 2 U.S. senators. The FBI sought Sandia’s help and answers that only experts at a world-class facility could uncover. Sandia was the first team to alert the FBI that the spores in all the letter-attacks had a common signature and were not weaponized— suggesting the spores had originated in the same source laboratory. DNA studies corroborated Sandia’s findings, instrumental to the FBI’s investigation.