California officials failed to prevent hundreds of sexual assaults at women’s prisons by systematically ignoring allegations of abuse, according to a report released by the Justice Department on Thursday.

The federal investigation, which began in 2024 with subpoenas for records related to sexual assault or harassment dating back years, found that inmates at two state-run women’s prisons routinely had their constitutional rights violated and that California prison officials failed to adequately establish safeguards required under the 2003 Prison Rape Elimination Act. The two prisons are the Central California Women’s Facility in Chowchilla and the California Institution for Women in Chino.

The Justice Department said that state prison officials must take remedial action, including putting more transparent systems in place for investigating abuse claims, within 49 days. If sufficient improvements are not made, the department said, it may sue to force changes.

“This deliberate indifference to the suffering of female prisoners at the hands of prison staff is illegal,” Harmeet K. Dhillon, the assistant attorney general for the department’s civil rights division, said in a statement announcing the findings.

California prison officials said they began reforms long before the most recent federal investigation, including by expanding surveillance camera coverage of facilities and improving processes for prisoners to report abuse.

The state also said that the findings of the new report appeared to conflict with the findings of last year’s federally mandated compliance audits, which found that both prisons met all 45 of the standards laid out in the Prison Rape Elimination Act.

“Sexual abuse, sexual harassment and retaliation against individuals in our care are unacceptable,” Will Matthews, a spokesman for the California Department of Corrections and Rehabilitation, said in a statement.

He added that the department would continue to work with federal officials to address their recommendations.

The investigation into women’s prisons run by the state of California began during the Biden administration not long before the government announced that it would close a federal women’s prison in the state that had become infamous for rampant sexual abuse.

In December 2024, the U.S. Bureau of Prisons reached what lawyers described as a landmark agreement to pay $116 million to settle lawsuits by 103 women who said they had been sexually abused at that shuttered prison, the Federal Correctional Institution in Dublin, Calif.