Robert D. Stiger, 58, a retired Navy commander and Vietnam War veteran whose 21-year military career included assignments in counterintelligence and criminal investigations, died of a pulmonary disorder June 24 at Inova Fairfax Hospital.

Cmdr. Stiger, who had emphysema, underwent a single-lung transplant procedure in 1995 and participated in promoting awareness for organ donation and transplantation. He also took part in support and mentorship programs for other lung transplant candidates and their families.

A Sterling resident, he was a native of Wilkes-Barre, Pa., and a 1963 graduate of the U.S. Naval Academy. Upon graduation, he was among a handful selected to be commissioned as a special duty officer. From there, he attended the Defense Intelligence College in Washington, the Armed Forces Staff College and numerous technical, management and specialist schools.

During the Vietnam War, he served in combat intelligence with the Riverine Assault Force in the Mekong Delta. In the 1960s and '70s, he served two tours of duty with the Central Intelligence Agency, where, among other duties, he served as executive secretary of a high-level panel providing scientific and technical advice to the CIA director.

Other military assignments involved scientific and technical analysis of weapons systems and national-level strategic and political analysis.

His military honors included the Bronze Star, Meritorious Service Medal and the Navy Commendation Medal.

After his military retirement in 1984, he worked 10 years as director of business development for Computer Sciences Corporation in Falls Church.

Survivors include his wife of 36 years, Elaine A. Stiger of Sterling; two children, Diane Marie Gibbs and David John Stiger, both of Ashburn; his mother, Victoria F. Stiger of Wilkes-Barre; and a sister.