Charles J. (Charlie) Spell, 39, who was found shot to death early Sunday on Blunt Road in Gaithersburg, was a senior technical adviser with the Department of Energy.

Montgomery County police said they arrested Gerald S. Sibley on Sunday night and charged him with murder in the death of Mr. Spell, who lived in Gaithersburg.

Mr. Spell had worked for the Department of Energy since it was established in 1977. At the time of his death he was senior technical adviser to the director of the office of plans and technology assessment for fossil energy.

He helped direct the coal-leasing liaison committee between the departments of Energy and Interior, which helped set coal-production goals from government-owned lands.

He also was head of an Energy Department study group working on the future transportation requirements of getting coal from the mines to the market.

Mr. Spell was coordinating the new interagency task force on coal exports recently established on orders from President Carter.

Mr. Spell was native of St. Petersburg, Fla., and earned a bachelor's degree in industrial engineering at the University of Florida. He also earned a master's degree in business administration at Florida State University.

He worked as a civilian engineer for the Air Force in Georgia and as an assistant to the director of support operations at the Kennedy Space Center in Florida before coming to Washington in 1972.

He spent two years in the office of aeronautics and space technology of the National Aeronautics and Space Administration before joining the old Federal Energy Administration in 1974.

A year later, he joined the Energy Research and Development Administration and worked in plans and policy. He worked there until ERDA became part of the new Department of Energy.

Survivors include his wife, Eva, from whom he was separated, of Gaithersburg; a son, Charles J. Jr., who lived with Mr. Spell in Gaithersburg; his mother, Evelyn Garcia, a brother, Roger, and a sister, Evie Fernandez, all of Tampa, Fla.