An off-duty Sonoma County Sheriff's deputy fatally shot the mother of his three children at her apartment over the weekend and later killed himself in the parking lot of the coroner's office, Santa Rosa police said.

An off-duty Sonoma County sheriff's deputy killed his ex-girlfriend and then himself in an unusual tragedy that has shocked the entire department, authorities said on Monday.

A Sonoma County Sheriff's deputy allegedly killed the mother of his three children before fatally shooting himself during a standoff with police and deputies on Monday morning.