Montgomery County Police Major Stephen Filyo, 44, who was chief of the investigative services bureau, died of cancer Sunday at the National Institutes of Health.

Maj. Filyo had been a member of the Montgomery County Police force for the last 21 years. He began his career as a Bethesda District patrol officer. In 1965, he was assigned to the Juvenile Divison and remained there until 1973. He served first as an investigator and was deputy commander when he was transferred.

He was promoted to captain in 1973 and two years later became chief of the department's Administrative Services Bureau. From 1977 to 1979, he was commander of the Wheaton-Glemmont District Station. His last assignment was as chief of the investigative services bureau.

Maj. Filyo was a native of Central City, Pa. He spent two years in the Army before coming to the Washington area in 1958. He joined the Montgomery County Police a year later. He was a 1973 graduate of the University of Maryland, where he earned a bachelor's degree in police administration.

He was a resident of Wheaton and a member of the Orthodox Greek Catholic Church of the Holy Resurrection in Potomac.

Survivors include his wife, Gail, and a daughter, Terri, both of Wheaton; a son, Stephen Jr. of Gaithersburg; his mother, Susan Filyo of Central City, Pa., and five sisters, Ann Maddy, Olga Ference, and Helen Kott, all of Central City, Julie Yaskola of Windber, Pa., and Pauline Sadosky of Cockeysville, Md.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society, to the Stephen Filyo Sr. Scholarship Fund, c/o the Rockville District Police Station, 1451 Seven Locks Rd., Rockville, 20854, or to the Orthodox Greek Catholic Church of the Holy Resurection, 10201 Kentsdale Dr., Potomac.