Shawnie Yamaguchi was a CIA agent who was sent to monitor Jilly Kitzinger. She came to Jilly, claiming to be looking for an internship for a PR and asked to work for her. Jilly eventually accepted the offer, and asked the woman to bring her a sandwich and to hire a prostitute for Oswald Danes. After Jilly was assaulted by Oswald, she explained to Shawnie that she was planning to hold a press conference to let the world know what Oswald had done. An agent of the Families who Jilly had met at the miracle rally soon arrived and shot Shawnie, reducing her to category one. The man explained that the Shawnie was actually working for the CIA. (TW: End of the Road)
"Shawnie Yamaguchi" was most likely an alias used by this CIA agent.