Tulare County sheriff's detectives are investigating Brittney Steenbergen's disappearance from her home in Plainview as suspicious.
Steenbergen's estranged live-in boyfriend Adel Hussein has been identified as a person of interest in the case and is also being sought.
Steenbergen and Hussein's four children are with other family members.
Steenbergen was last seen on Saturday at her Plainview home. She is described as having brown hair and being 5'8" in height and weighing 200 pounds.
Hussein was last seen in the Tipton area around 6 p.m. on Tuesday. He is known to frequent the Plainview and Porterville area.
He is described as being 5'4" in height, 200 pounds, and having black hair and brown eyes. He was last seen wearing a grey hat with a "B" on it, black jacket, blue jeans and black shoes. He is known to drive a 2007 Toyota RAV4 license plate No. 5XNS883.
Anyone with information about the whereabouts of Steenbergen or Hussein is urged to call the Tulare County Sheriff's Office at (559) 733-6218. Tips may be submitted anonymously at email@example.com or by text or voicemail at (559) 725-4194.