Someone who identified as her sister contacted me. According to the exchanges we had, Susan was last seen on April 8th, 1975 in Decatur, Georgia, which was her 16th birthday. She was previously in the Seattle, Washington area. In Seattle, she lived with her brother Frank Redding Jr. but he, according to my source, couldn't deal with Susan when she was starting to rebel. On April 8th, 1975, Susan was in the company of a white male who was a lot older than her. Susan was apparently going to the dry cleaners that day. She hasn't been seen since according to the sister's rendition of events.
Susan fell out with her mother. Apparently, one of the men Susan kept company with almost killed one of her brothers when he protested their relationship. Susan, according to the sister, may have been a prostitute at some points in her life.
A phone call likely happened in October 1982. At that time, the grandmother died and Susan seemed to be calling the grandmother's house to discuss the death with whoever answered the phone. This suggested to me that Susan was in the family grapevine somehow unless she heard about the death through newspapers. Susan's family is large. An aunt was the phone answerer the day she called. Susan hung up abruptly when she heard her mother's voice in the background. If true, Susan seemed to be alive and well in October 1982. In my opinion, this was a voluntary disappearance at first but Susan's fate is still something living family members want information on, including a 96-year old mother as of the time of this post.