Mark Schroeder, 55, was last known to be at his home in the 2900 block of Morse Glen Lane sometime during the day on Monday. He may be with his girlfriend, 52-year-old Janette DeGrace.
"He is considered at-risk because he is missing under suspicious circumstances," stated a press release from the Sacramento County Sheriff's department.
Schroeder drives a 1999 Porsche 911 with the California license plate of 5DRB566.
Schroeder is white, 5 feet 10 inches tall, about 140 pounds with collar-length brown hair and brown eyes. DeGrace is white, 5 feet 3 inches tall and about 130 pounds with brown hair and blue eyes.
Anyone with information about Schroeder is asked to call the sheriff's department at (916) 874-5115. Anyone with information about DeGrace is asked to call the police department at (916) 264-5471.