Edwin Janss Jr

California real estate developer who helped expand and develop the ski resorts of Sun Valley and Snowmass, fell to his death Thursday when he jumped from the 12th story of a building in Santa Monica, Calif. Born in Los Angeles, he was the third generation of a family of real estate developers. His grandfather, Dr. Peter Janss, developed East Los Angeles. His father built Holmby Hills, an enclave off Sunset Boulevard between Bel Air and Beverly Hills, and developed Westwood Village. The father, Edwin Janss Sr., donated 385 acres of Westwood to the University of California for its Los Angeles campus. He and his brother William developed Thousand Oaks, a community north of Los Angeles, in 1955.Janss Investment Corporation bought the Sun Valley ski resort in Idaho from Union Pacific Railroad in 1964 and began its expansion. The corporation sold it in 1977. The brothers also developed Snowmass in Colorado, near Aspen. At the same time Mr. Janss was building resorts he was protesting the Vietnam War and collecting art. In 1968, he belonged to an organization of corporate executives, Business Executives Move for Vietnam Peace, and won a place on the ''enemies list'' of former President Richard M. Nixon's for his antiwar stance. With his wife, Ann, he built a discriminating art collection over 35 years.Besides his wife, Mr. Janss is survived by a daughter, Dagny Corcoran, of West Los Angeles; two sons, Peter, of Bliss, Idaho, and Lawrence, of Thousand Oaks, Calif.; his brother, William, of Sun Valley and four grandchildren.