DUPO • Melody Day spent most of the past 26 years searching for clues to find her missing mother — and collecting records and online information that might someday help identify a body, if it came to that.

On Tuesday, she said she was disappointed to learn that the key to the mystery had been sitting unnoticed in a Missouri Highway Patrol file.

In 2010, Day had learned from a Facebook posting that the decomposing body of a woman who apparently was beaten to death, had been found Aug. 26, 1990, in a secluded area of Pike County, Mo. That was the same month her mother, Cynthia Day, 38, was last seen.

There were similarities. Both women had hysterectomies, for example, and similar jewelry, body size and hair color.

Melody Day believed it was her mother. But she and her sister, Kimberly Day, both of Dupo, were told by Pike County sheriff’s officials there was no way to be sure.

DNA testing was available but not as common in 1990. And there was no tissue left to test, because the victim’s bones had been boiled to preserve them and accommodate an attempt at facial reconstruction.