Castillo’s remains were found in a remote location in Antelope Valley, the Simi Valley Police Department announced Sunday. Police named Castillo’s ex-husband, 25-year-old Zarbab Ali of Hawthorne, as the prime suspect. He was arrested Sunday afternoon at that parent’s home in Victorville in connection with the homicide, Simi Valley police said. “This investigation has evolved rapidly over the past few days,” police said. “This case is still under investigation and some details cannot be released for legal and investigative reasons. The Simi Valley Police Department will release additional details about this case when they become available.” Rachel Castillo, a missing woman from Simi Valley, California, is pictured in photos released by her family. Castillo family Local police said earlier Sunday that a “significant amount of blood” was left at the scene after Castillo’s disappearance. “Upon further investigation, a significant amount of blood was located in her home. Rachel’s whereabouts are unknown. Given the circumstances, Rachel is believed to be in danger,” the Simi Valley Police Department said in an earlier statement. Castillo, 25, has two children and lives with her sister a few miles away from their parents, her family told ABC affiliate KABC. She had dropped off her children with their father Thursday morning before she disappeared, her family told KABC. “As soon as I saw the blood, that’s when I knew something was wrong,” Emily Castillo, her sister, told the local station. He had returned home Thursday night. “So I called my mom to let her know to come over and then I called 911 right away.” Many of her belongings — including her phone, keys and car — were still in the house, her family said. Anyone with information can contact the Simi Valley Police Department at 805-583-6950.