For the investigators at the Philadelphia Medical Examiner's Office, this is one of the rare situations in which they have not yet put a name to one of the city's dead.
Many cases are straightforward. Some a bit harder. A few - including this one, perhaps - impossible.
The morgue detectives will tell you that seldom, if ever, do their cases play out as they do on TV, where CSI programs mix science with fiction to produce entertaining mysteries with neatly packaged endings.
"On TV there is an element of truth . . . but they take an element of truth and make it fantastic," said David Quain, forensic-services manager at the Medical Examiner's Office. "But it really isn't the way it works."
In the real world, investigators carry photos of the dead or of tattoos on discolored flesh and show them around. They seek out dental records and X-rays and even photographs of smiling faces that can be used to see whether the teeth match those of the deceased.
Most often, they take fingerprints - if the dead still have flesh - and wait for a match.
Even that, Quain said, might not yield a proper identification, because criminals don't always give their real names when arrested, making it harder to find next of kin.
Of course, there's DNA, but if detectives have no idea who the person is, DNA is of little use because it must be compared to that of a blood relative.
And it takes time.
"DNA is kind of a last resort," Quain said. "Fingerprints can be done in a day. Dental workups can be done in a day. DNA can take weeks or months."
DNA is used to confirm an identity, not establish it, he said.
A team of 10 investigators, backed by technicians, works around the clock, staffing a communications desk and going out to scenes of homicides or unusual deaths, Quain said.
About 300 bodies or sets of remains arrive at the Medical Examiner's Office each year as unknowns.
Many are quickly identified.
For example, word of a fatal shooting can spread quickly through a neighborhood, carrying the bad news to the victim's family.
Shortly thereafter, relatives show up at the morgue and make an ID.
But even then, Quain said, investigators have to be careful. He recalled a case in which a woman who heard her daughter had been shot went to the Medical Examiner's Office, on University Avenue, and made an identification - only to be doubly shocked when her daughter returned home later.
"She was so upset and so distraught, she never actually looked closely. She already accepted" it was her daughter, Quain said. "That's why we like to do scientific means whenever we can, fingerprints being one of them."
Besides identifications, investigators help pathologists determine manner of death: natural causes, homicide, suicide or an accident. The medical examiner establishes the cause of death if a doctor has not provided one.
Along with fingerprints and dental records, tattoos - now common on both men and women - and body piercings are helping more and more to identify bodies, morgue detectives have found.
A trend in which relatives get a tattoo with a victim's name - or nickname - and sometimes the date of death has assisted investigators in recent years, Quain said.
"They are one more way to put the pieces together," he said, adding that running the tattoo information through the office's database has helped investigators find kin.
Those who remain unidentified are eventually cremated after experts take a DNA sample for possible future analysis; the ashes are stored at the morgue with the cremains of those who were identified but unclaimed for whatever reason.
How the woman found with the sorority key died, like her identity, remains unknown. The Alpha Zeta Beta key also was inscribed with "Life Member" and "June 2, 1946." Four red acrylic fingernails also were recovered.
Anthropological examination indicates the woman was white, 5-foot-4 to 5-8, and 34 to 62 years old with brown or auburn hair.
If all efforts fail to identify the woman, chances are that her remains will one day be cremated and end up in the modern-day equivalent of potter's field.
Contact staff writer Joseph A. Gambardello at 215-854-2153 or firstname.lastname@example.org.