Question: What city did the key suspect in the 2001 anthrax attacks work in?

Context paragraphs:
Anthrax War: Anthrax War is a 2009 documentary film about the 2001 anthrax attacks and the rise of today's biomilitary industrial complex that was co-produced by the Canadian Broadcasting Corporation and ARTE-France.  Broadcast internationally, it was nominated for the 2009 Prix Europa for Outstanding Current Affairs Broadcast.  It also screened at the Frontline Club in London, the IDFA Fest in Amsterdam, the Tri-Continental Film Fest in Johannesburg, and the 9/11 Film Festival in Oakland, California, among other venues.

Bruce Edwards Ivins: Bruce Edwards Ivins (April 22, 1946 – July 29, 2008) was an American microbiologist, vaccinologist, senior biodefense researcher at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, and the key suspect in the 2001 anthrax attacks.

Fort Detrick: Fort Detrick is a United States Army Medical Command installation located in Frederick, Maryland.  Historically, Fort Detrick was the center of the US biological weapons program from 1943 to 1969.  Since the discontinuation of that program, it has hosted most elements of the United States biological defense program.

Prime suspect: A prime suspect or key suspect is a person who is considered by the law enforcement agency investigating a crime to be the most likely suspect.  The idiom "prime suspect" believed to have originated in 1931.  "Key suspect" is seen as early as 1948.

Dale Watson (FBI): Dale L. Watson is the former Assistant Director for the Counterterrorism Division of the FBI, as such he headed the FBI investigation into the September 11, 2001 attacks and the 2001 anthrax attacks.

Anthrax hoaxes: Anthrax hoaxes involving the use of white powder or labels to falsely suggest the use of anthrax are frequently reported in the United States and globally.  Hoaxes have increased following the 2001 anthrax attacks, after which no genuine anthrax attacks have occurred.  The FBI and U.S. postal inspectors have responded to thousands of "white powder events" and targets have included government offices, US embassies, banks and news organizations.

Irradiated mail: Irradiated mail is mail that has been deliberately exposed to radiation, typically in an effort to disinfect it.  The most notable instance of mail irradiation occurred in response to the 2001 anthrax attacks; the level of radiation chosen to kill anthrax spores was so high that it often changed the physical appearance of the mail.

2001 anthrax attacks: The 2001 anthrax attacks, also known as Amerithrax from its Federal Bureau of Investigation (FBI) case name, occurred within the United States over the course of several weeks beginning on September 18, 2001, one week after the September 11 attacks.  Letters containing anthrax spores were mailed to several news media offices and two Democratic U.S. Senators, killing five people and infecting 17 others.  According to the FBI, the ensuing investigation became "one of the largest and most complex in the history of law enforcement."

Robert Stevens (photo editor): Robert K. "Bob" Stevens (June 20, 1938 – October 5, 2001), an American photojournalist for the "Sun", a subsidiary of American Media, located in Boca Raton, Florida, United States was the first journalist killed in the 2001 anthrax attacks when letters containing anthrax were mailed to multiple media outlets in the United States.  The anthrax attacks also killed four others in the United States and sickened seventeen others.

BioWatch: BioWatch is a United States federal government program to detect the release of pathogens into the air as part of a terrorist attack on major American cities.  Reportedly operating in Philadelphia, New York City, Washington, DC, San Diego, Boston, Chicago, San Francisco, Atlanta, St. Louis, Houston, Los Angeles and 21 other cities, the BioWatch program was created in 2001 in response to the increased threat of bioterrorism sparked by the 2001 anthrax attacks, and was announced in President George W. Bush's State of the Union Address of 2003.

Supporting paragraphs: Bruce Edwards Ivins Fort Detrick
Answer: Frederick, Maryland