Mark J. Mikulski, an FBI agent who headed technology programs that worked to detect terrorist threats, died Feb. 25 at the Reston Hospital Center. He was 50.

The cause was multiple myeloma, said his ex-wife, Molly Ehrenreich.

Mr. Mikulski was a supervisory special agent at the FBI for nearly 20 years, working in cybercrime, evidence confiscation, technology crime and hazardous evidence response. His family said his cancer developed as a result of exposure to diesel fuel during the Sept. 11, 2001, attacks.

Mark Joseph Mikulski was a native of Buffalo and a 1985 graduate of the University of Buffalo. Before joining the FBI in 1995, he was a computer data form specialist at Frontier Science & Technology Research Foundation and an Army reservist.

He was a Boy Scouts troop leader for the past year and was a representative to the FBI Agents Association. He was a resident of South Riding, Va.

His marriage to Molly Ehrenreich ended in divorce. Survivors include a son, Scott Mikulski of South Riding; a sister; and two brothers.

— Hoai-Tran Bui