The Simi Valley Police Department in California is searching for 25-year-old Rachel Castillo.
CNN  — 

Authorities in California are searching for a 25-year-old woman believed to be “at risk” after a “significant amount of blood” was found in her home, according to police.

Officers with the Simi Valley Police Department responded to a call of suspicious circumstances at the residence of Rachel Castillo Thursday night, a news release from the department said.

Upon further investigation, Castillo’s whereabouts remain unknown, police said.

Rachel’s mother, Robyn Castillo, told CNN that Rachel’s sister, Emily Castillo, found the blood at the home Thursday evening.

“She entered the home, saw the blood and then called me and then called 911,” Robyn Castillo said. “So, I quickly rushed over, and we both entered the home again.”

Emily had searched the property for Rachel before her mother and the police arrived, but was unable to find her, Robyn said. She and her daughter then left the home to avoid contaminating the scene.

Rachel Castillo has two sons, ages five and two.

Robyn described her daughter as a “really great mom to her sons, a good daughter, a good sister, and a good friend.”

Rachel’s two sons, ages 5 and 2, had been picked up from the home earlier that morning by their father, Robyn said.

“We’re hoping that somebody has some information and that they’ll come forward so that we can bring her back home to her family and her sons,” she added. “It’s been very difficult, we’re just taking it day by day and moment by moment and helping police as much as we can.”

Rachel is studying to become a marriage and family therapist, her mother said. She added that Rachel loves to help people and get them the resources they need.

Police described Rachel as 5’2” tall, weighing 105 pounds, with brown hair and eyes.

Anyone with information regarding her whereabouts is asked to contact the Simi Valley Police Department.