The family of a Southern California yoga enthusiast who disappeared during a retreat in Guatemala in October last year are expressing frustration over their inability to speak with the last person known to have seen the victim alive. About the disappearance: Nancy Ng, a 29-year-old special needs teacher from Monterey Park, California, went missing on Oct.19 during a yoga retreat at Lake Atitlán in Guatemala. Desperate for answers: Determined to find her, Nancy's family traveled to Guatemala and hired a private search and rescue team to scour the lake.