In Fall 1996, a woman checked into an upscale hotel in downtown Seattle, paid cash, and registered under the name, Mary Anderson. She provided a false number with a NY area code and a false address that featured a NY zip code. Once she checked in, she went to room and reportedly had no further contact with hotel staff or room service. No calls were made from the room. She was eventually discovered when she failed to check out of the room. She was discovered lying on her back, on her bed, with a suicide note mentioning that she had no family and that she did not care what was done with her body. The cause of death was determined to be cyanide poisoning.
There were few clues left at the scene. She had no identifying documents, she paid for the room in cash, and there is speculation she might have removed her dental plate to further obstruct efforts to identify her. Investigators searched databases using dental records and fingerprints. There were no matches. A DNA profile was developed for "Mary Anderson" and searched in the CODIS database, but there were no matches. Local and national media appeals, as well as multiple forensic facial reconstructions have failed, so far, to provide leads.
In 2021, King County Medical Examiner's Office has partnered with Othram to use advanced DNA testing and forensic genealogy to establish an identification of, or to find the closest living relatives to the unknown woman. Funds to support the case are being raised on the DNASolves Crowdfunding platform. The case is also logged in NamUs as #UP12916.