Fort Detrick's anthrax mystery

Assaad said he filed a formal complaint with the Army after his supervisor ignored him. The commander of the U.S. Army lab investigated the complaint and found in Assaad's favor, and singled out Zack and Rippy for criticism for being at the center of the Camel Club. (The Army investigation documents further revealed that the two, both married, were also having an affair.)

"Based upon your complaint, I directed that an informal investigation be conducted," USAMRIID's then-commander, Col. Ronald Williams, wrote Assaad in a memo in August 1992. "The investigation revealed that Lieutenant Colonel Zack and Dr. Rippy had participated in discriminatory behavior.

"On behalf of the United States of America, the Army, and this Institute, I wish to genuinely and humbly apologize for this behavior," Williams' memo continued.

Before the investigation ended, both Zack and Rippy were reprimanded. Then Zack left USAMRIID in December 1991, first heading to the Army's Walter Reed Institute, then going to the private pharmaceutical company Eli Lilly, and then to a company in Colorado acquired by St. Louis' Nexstar Financial Management. Several calls by Salon to his last known phone number and address in Boulder, Colo., went unreturned, and Nexstar says it no longer has any record of Zack. Rippy, who left USAMRIID shortly after Zack, in February 1992, worked for a while at Eli Lilly, but could not be located by Salon.

Assaad is puzzled that after clearing him of the accusation that he could be a bioterrorist, the FBI showed no interest in talking with him about his days at Fort Detrick. "The whole world wants to talk to me, except the FBI," he said, as his lawyer's phones rang nonstop this week, with media organizations seeking interviews with him. "Something's wrong here."

But while the FBI may not be interested in talking with Assaad further, federal authorities increasingly seem to believe that the anthrax letters were sent by a U.S. government scientist -- and not by the Iraqis or al-Qaida, as some hawks have continued to insist over the past few months, while hundreds of Islamic and Arab-born immigrants have been questioned and detained by the FBI and INS.

"I can tell you there are scientists out there who do have military connections that we are focusing on, at least that connection," Kevin Donovan, FBI special agent in charge of the Newark bureau, said at a press conference Wednesday.

For his part, Assaad says, "I want people to know the truth," and wants to show the American people that Arab-Americans are not the enemy. Should the FBI trace the anthrax attacks back to his former lab, Assaad may have gone a long way toward his goal.

• View blog reactions