He's currently being held on a "level 1 safety precaution," which is implemented when someone exhibits suicidal behavior.
SIMI VALLEY, Calif. (KABC) -- The ex-husband of the Simi Valley mother of two who was found dead over the weekend has been formally charged with her murder.
Zarbab Ali, a 25-year-old Hawthorne resident, did not appear in court during a hearing Tuesday.
The murder charge against him was filed Tuesday morning where he was also charged with a special allegation of lying in wait and personal use of a knife.
Authorities said Ali is currently being held on a "level 1 safety precaution," which is implemented when someone exhibits suicide thoughts or behavior.
Rachel Castillo, 25, was reported missing after her sister found a bloody scene at her home on Nov. 10.
The discovery triggered a search for the mother, whose cellphone, car keys and vehicle were still at the home she shared with her sister Emily.
On Sunday, Simi Valley detectives say they found human remains in a remote location of the Antelope Valley. The medical examiner identified the remains as Rachel.
Ali was arrested at his parents' home in Victorville "in connection to Rachel's homicide."
Rachel's father, Christopher Castillo, noted that during the search for his daughter he "had a suspect list in mind and I had a theory regarding the crime and what ultimately ended up happening and the reality of what had taken place."
Asked if there had been any previous warning signs about Ali, Christopher Castillo replied: "I would just say that violence has become a part of what is happening in this country, and for whatever reason, I'm not exactly sure why younger people seem to think that violence is acceptable.
"I mean, there's always been murders. There's been husbands who killed their wives since the dawn of time," the father said. "But it just seems to be more prevalent in this country. There seems to be less consequences for doing violence. And it's something that really has to stop."
Rachel was the mother of two young boys, who were found safe early on during the search for her.
Her father said he was working with the San Bernardino County Department of Children and Family Services to get the children into the custody of his oldest daughter, "who Rachel had indicated that she wanted the children to go to."
He paid tribute to the multiple law enforcement agencies that participated in the search for his daughter, noting the "thousands and thousands of hours put into this case by Simi Valley Police Department and later the FBI," including the bureau's Evidence Response Team.