Douglas County sheriff's investigators are seeking the whereabouts of a 63-year-old Gardnerville woman missing since Friday.Sgt. Jim Halsey said the woman, Kathy Arlana Hammond, was reported missing on Sunday by a friend who last saw her at 1 p.m. Friday. The friend said Hammond is reported to be mentally unstable, and has threatened suicide in the past.She was reported to be driving a 4-door teal green 1993 Subaru Legacy sedan, California license plate 3CKF797.Hammond is 5 feet, 2 inches tall, 135 pounds, medium build with fair skin, long straight brown hair and brown eyes. She was last seen wearing blue …