Harry E. Williams, 57, a retired arson investigator with the Arlington County Fire Department and manager of a country and western music group, died Saturday at Commonwealth Doctors Hospital in Arlington after a heart attack.

Mr. Williams served with the Arlington Fire Department for 19 years, the last seven of them as an arson investigator, before retiring in 1974. He was a member of the Professional Fire Fighters Association and conducted seminars in arson investigation through the association throughout the Washington metropolitan area. He also was a member of the International Association of Arson Investigators.

For the past 10 years, Mr. Williams had been manager of the Gracie Williams Show, a country and western music group featuring his daughter, Grace Ellen Delozier. He was a member of the Country Music Entertainers Benevolent Association.

Mr. Williams was a resident of Lorton. He was a past president of the Upper Pohick Community League and had been board chairman of the Sydenstricker Methodist Church in Springfield. He was a Mason and a member of the Moose and the Veterans of Foreign Wars.

Mr. Williams was born in Charlotte Hall, Md., and was reared in Springfield. He served in the Army from 1940 to 1946 and was in Europe during World War II.

In addition to his daughter, of West Springfield, his survivors include his wife of 36 years, Sarah Madge Williams, of Lorton; two other daughters, Teresa M. Johnson of Miami Springs, Fla., and Eileen W. Sickel of Manassas, and one grandchild.