Susan LaRosa was 20 years old and already a mom to three young children when she disappeared in 1975. She had dark black hair, cut just above her shoulders. She was petite, 95 pounds. Her husband said she left their apartment one evening to get diapers and baby formula and never returned. That’s the extent of what you’d know about Susan LaRosa if you read about her case in the newspapers. But after years of looking into her story, and speaking with family members who are finally ready to talk, the mystery takes a disturbing turn as a person of interest emerges