Donald J. Lawton, 79, who served in the D.C. police department and the U.S. Secret Service during a four-decade career, died April 5 at his home in Annandale.

He had cancer, said his nephew Howard Shea.

Mr. Lawton was a police officer from 1957 to 1972 and a Secret Service agent from 1962 to 1982. He remained associated with the Secret Service as an independent contractor through 1996.

Donald James Lawton was born in Newport, R.I., and served in the Marine Corps from 1954 to 1956. His memberships included the Association of Former Agents of the U.S. Secret Service.

His marriage to Norma Lawton ended in divorce. He had no immediate survivors.

— Emily Langer