Bertha Sieg RESOLVED Bertha, circa 1994 Missing Since 02/08/1994 Missing From Duncanville, Texas Classification Endangered Missing Age 14 years old Height and Weight - Distinguishing Characteristics - Details of Disappearance Bertha disappeared from Duncanville, Texas on February 8, 1994. In June 2016, she was found deceased. Further details are unavailable. Investigating Agency - Source Information The National Center for Missing and Exploited Children . .