The sheriff's office says 45-year-old Sgt. Chad Bruce's family found him unconscious in his bed.
Bruce was pronounced dead a short time later.
His cause of death has not yet been determined.
Investigators say it appears Bruce died of natural causes.
Bruce began working at the sheriff's office in June 2002.
He was promoted to sergeant in 2018 before joining the Tulare Area Gang and Narcotics Enforcement Team.