Cynthia Louise Day (November 11, 1952 - c. August 26, 1990) was a woman whose remains were discovered in a box in rural Pike County, Missouri.
She was identified via fingerprints in 2016. Her death is currently being investigated as a homicide.
In 1990, Day was living in National City, Illinois, with her long-term boyfriend and struggling with drug & alcohol abuse. She was last seen on August 10 of that year after her daughters visited her with her new grandson. That same day, Day confided in her daughters that she felt her relationship with her boyfriend had soured and that she was planning to leave him. Her daughters believed her struggles with drugs and alcohol were what increased tensions between Day and her boyfriend. Though, several days later when her daughters came to visit again, she was missing alongside her belongings and boyfriend. Her boyfriend would be sighted by one of the daughters weeks later, though he claimed he had no idea where Day was before vanishing again.
Fourteen years later, one of Day's daughters would discover that an official missing person's report for her mother was never filed. A proper report was filed that year, and the daughter began to conduct a personal investigation alongside making a website about the case.
On August 26, 1990, hikers passing through rural Pike County, Missouri, came across a box of human bones. Tests indicated that the remains belonged to a white female, but further developments were not made until 2016 when an investigator at the Missouri State Highway Patrol Division of Drug and Crime Control received an anonymous tip. The unidentified caller requested the investigator look into Day's case for the remains as she was potentially the mother of an acquaintance.
Previously, the Day sisters had requested authorities use DNA to find their mother and potentially match her to the remains found in the box in Missouri, though they were denied when they were told the bones had been boiled by lab technicians which was a common practice before DNA testing was widely available. Nonetheless, detectives began looking into whether the remains could be tested again only to match the remains with a single fingerprint they had on file for Day after a misdemeanor charge.
in 2016, Cynthia Day was officially identified and returned to her family. Her death is currently being investigated as a homicide and a possible person of interest was mentioned, but authorities have declined to release further information.