Peter Helmuth Brinitzer, 77, a retired Army intelligence officer who spent more than three decades as a citizen activist in Fairfax County, died of kidney failure June 11 at his home in Alexandria.

In 2002, Col. Brinitzer was honored by the Fairfax County Board of Supervisors as "an integral, major part of public life in the Mount Vernon District." He also was described by an activist as a "technician of democracy" -- an individual who works behind the scenes without compensation to improve the county.

Col. Brinitzer, who moved to Stratford Landing in 1967, urged the county supervisor from the Mount Vernon area to help secure money from the state for new roads into the landlocked community, which had 450 homes and one connecting street. After that success, he used his leadership skills to plunge into other community issues.

Largely because of Col. Brinitzer's efforts, the cultural life of the Mount Vernon District was transformed, a 2003 Washington Post article said. He counted that among his top achievements, which also included having the Fairfax County Symphony perform for the first time in Fort Hunt High School.

Col. Brinitzer served as president of the Little Hunting Creek/Stratford Landing Citizens Association. He helped form and co-chaired the Mount Vernon Council of Citizens Associations, which named him its Citizen of the Year in 1997. He also was president of the Fairfax County Federation of Citizens Associations, a countywide group of more than 200 civic associations. He was chief of operations for the Stratford Recreation Association.

He was also a member of the Northern Virginia Regional Planning Commission; was chairman of the Fairfax County Planning Commission, of which he was a member for 12 years; and served on the county's Criminal Justice Coordinating Council and the Criminal Justice Advisory Board.

Before his career in civil activism, Col. Brinitzer had parallel careers as a high-ranking official in the Defense Intelligence Agency and as an Army Reserve colonel.

From 1976 to 1983, Col. Brinitzer was the defense agency's principal human-intelligence requirements manager, serving as chief of the collection management branch for seven years and as chief of the human resources division for three years. He was his department's designated guest lecturer at the Defense Intelligence College, Naval War College and other military educational institutions. Among many awards for his work at the agency, Mr. Brinitzer was given an Exceptional Civilian Service Medal in 1983.

His 30-year career in the Army Reserve also was concentrated in military intelligence. His last command, from 1976 to 1979, was with the 5th Psychological Operations Group, a 1,100-person unit in the active reserve structure. Col. Brinitzer was awarded a Meritorious Service Medal for his work in this command and the Legion of Honor for his service in the reserves.

Born in Breslau, Germany, Col. Brinitzer immigrated with his family to the United States in 1938 to flee the Nazis. He enlisted in the Army at 1944, at age 17; partly because he spoke German fluently, he was assigned to a military intelligence unit.

He participated in the Battle of the Bulge and in the remainder of the European campaign. He then conducted de-Nazification and intelligence collection activities in the Office of Military Government in Berlin through mid-1946.

He graduated from Syracuse University and attended George Washington University Law School before returning to Germany in 1950. He spent 15 years, largely in Berlin, engaged in various military intelligence roles, primarily in connection with the Air Intelligence Service of the Air Forces in Europe. He transferred to Washington in 1967, where he worked for the Defense Intelligence Agency until his retirement in 1986.

The small street in Stratford Landing leading to the community pool, which he helped run for 30 years, was named for him in March.

Survivors include his wife of 42 years, Donna Louise Brinitzer of Alexandria; two sons, Scott Roberts Brinitzer of Arlington and John David Brinitzer of Paris; and a grandson.