Scott Decker retired from the FBI as a supervisory special agent at the end of 2011, after 22 years of service. He spent his early FBI career in pursuit of bank and armored car robbers throughout Boston. Several of his cases formed the real-life basis of Warner Brothers’ 2010 full-length motion picture, The Town. He then gained a promotion and joined the Bureau’s fledging Hazardous Materials Response Unit in Quantico. On September 12, 2001, he led a team of FBI hazmat specialists to Ground Zero in New York City. Three weeks later, the country came under attack again, this time from anthrax. Before it ended, the anthrax attacks killed five people and permanently injured nearly two dozen more. Returning from New York, Decker requested assignment to the newly formed Amerithrax Task Force. Decker, with a PhD from the University of Michigan, coordinated the early genetics and DNA forensics of the investigation. He then went on to supervise a squad of agents, all with advanced science degrees, as they coordinated every forensic aspect of the case. Their work charted new ground and established the discipline of Microbial Forensics. In 2009, he and his team received the FBI Director’s Award for Outstanding Scientific Advancement.

Decker remains in contact with the agents, scientists, and postal inspectors who investigated the anthrax attacks. He is able to write authoritatively on the events that took place, many of which have never before been publicized. He knows the identities of each participant in every search and surveillance operation. He took part in the investigation’s largest episodes: the back-to-back searches of Steven Hatfill’s apartment (Hatfill would go on to be exonerated and successfully sue the Department of Justice for violating the Privacy Act); dive teams entering frozen ponds in Maryland’s Catoctin Mountains; returning in the spring and completely draining a pond; shutting down and searching the US Army’s premier biological research facility; collecting samples of anthrax bacteria from laboratories around the world; and interviewing the former head of South Africa’s biological weapons program in a tiny Cape Town office.

In The Mirage Man (2011, Random House), Pulitzer Prize winner David Willman recounts Decker’s contributions to the anthrax investigation, and NY Times bestselling author Richard Preston acknowledges him for assistance with The Demon in the Freezer: A True Story (2002, Random House). In 2008, the Washington Post featured Decker in a front-page article by two-time Pulitzer Prize winner and national security reporter Joby Warrick, “Trail of Odd Cells Led FBI to Army Scientist.” The Stevenson University Forensics Journal profiled Decker in its Spring 2014 issue, and he has presented seminars on the anthrax attacks at FBI Headquarters and major universities.

He has also appeared with Sandra Bullock in 2013's action comedy, The Heat and served as technical director for Golden Globe winner Jon Hamm's narration of the short film, History of FBI Weapons, which is presented daily during the New FBI Tour in the J. Edgar Hoover Building.