The phone call that would eventually unfreeze a 42-year-old cold case came in on Sept. 15. It was an inquiry between law enforcement agencies. Typical. Routine. Nothing hinting at the surprise lying ahead.

Yan Salomon, a senior investigator with the New York State Police, dialed up the detective bureau at the sheriff’s office in Sullivan County, a Borscht Belt strip of the Catskills Mountains about 70 miles northwest of New York City. The skeletal remains of a female had been found one county over. Salomon was struggling to identify the body, so he was going through regional missing person reports. Sullivan County had an open case of a missing woman that roughly matched the description. Could the local investigators check the case file, Salomon asked, to see if the missing woman had any living relatives? A DNA test could match – or rule out – the remains.

It was a long shot on two counts. For one, nearly 70,000 women over the age of 18 go missing in the United States each year. Many eventually show up. But as Esquire reported last year, by January 2016 there were still 21,894 active cases of missing women on the books, creating an endless – and sad – series of possible identities for the dead woman.

The Sullivan County case was also complicated by its age. It dated from 1975.

Detectives in Sullivan County dusted off the old case file in question anyway. The missing woman’s name was Flora Stevens. The Daily Freeman reports she was 36 at the time of her disappearance and working at a Catskills resort.

On August 3, 1975, Stevens’ husband dropped her off at a hospital in Monticello for a doctor’s appointment. But when he returned to pick her up, she was not there. She was never seen again.

Sheriff’s Detective Rich Morgan was assigned the Stevens file and tasked with connecting the dots between the 1975 disappearance and the remains discovered in New York. The time lag created considerable difficulties. Stevens’s husband had died in 1985, the Associated Press reported. By sifting through local and national databases, Morgan determined Stevens appeared to have no living relatives.

But Morgan did hit on a clue. Someone was using Stevens’ social security number in Massachusetts.

Eventually, the detective tracked the number down nearly 250 miles away to an assisted living facility in Lowell, north of Boston. Staff there confirmed the number belonged to a Flora Harris. She had been living at the facility since 2001.

“Same first name, different last name, but same birth date and social security,” the detective told CBS Boston.

On October 24, Morgan and another investigator traveled to the facility. They found a beaming 78-year-old woman with hair falling to her shoulders. The investigators showed “Harris” a picture of Stevens from 1975. “She says that’s me, or me, she responded with one word, me,” Morgan told the television station.

But the woman could offer investigators nothing more to clear up the mystery surrounding her disappearance.

She suffers from dementia. The details of the last 42 years have been blotted out by her condition. “We really don’t know the circumstances of why or how she disappeared. She had psychiatric problems leading up to that point,” the detective said.

Medical records for Flora Harris indicated she had previously spent time in a nursing home in New Hampshire and Roosevelt Hospital in New York City, according to a news release from the sheriff’s office. Her medical records stretched back 30 years, then stopped. There does not appear to be anything else throwing light on Stevens’s lost years.

But with Flora Harris now confirmed as Flora Stevens, Sullivan County can close the case.

“It is not too often that you get to solve a 42 year old missing person case,” Sheriff Mike Schiff said in a release.