A Montana sheriff says investigators have solved a 45-year-old double slaying using a genealogy database to match DNA from the crime scene with the genetic profile of the now-deceased suspect.

Yellowstone County Sheriff Mike Linder said Monday that investigators believe Cecil Stan Caldwell killed Linda and Clifford Bernhardt, whose bodies were found in their Billings-area home in November 1973.

No motive was given. Caldwell, a longtime city employee, died in 2003.

The case remained cold until 2004, when it was revived after DNA was extracted from evidence from the crime scene.

In 2015, authorities enlisted a Virginia technology company to analyze the DNA, ultimately narrowing the suspects to Caldwell and his brother.

Linder says investigators eliminated the brother as a suspect leaving only Caldwell, a former co-worker of Linda Bernhardt.