SCOTT CITY, Mo. (AP) — Investigators in southeast Missouri dug for evidence this past week hoping for clues in an unsolved crime from four decades ago, but once again, they came up empty.

The Southeast Missourian reports that it was the latest disappointment in the 40-year-old disappearance of Cheryl Ann Scherer, a cold case that has baffled law enforcement and left Scherer’s family struggling to find closure.

The Scott County Sheriff’s office said little after the dig on Monday, other than the focus was on a field near a county road. The sheriff’s office, the FBI and the Missouri State Highway Patrol all participated.

Scherer was 19 when she disappeared from her job at the Rhodes Pump-Ur-Own gas station in Scott City the morning of April 17, 1979. Authorities believe Scherer may have been kidnapped.