LOS ANGELES (AP) — Nearly all inmates have been transferred out of a troubled women’s prison set to be shut down in California, and U.S. senators on Wednesday demanded an accounting of the rapid closure plan for the facility where sexual abuse by guards was rampant.

As of Tuesday only “a small group” of women were still being held at FCI Dublin, with the majority of its 605 inmates having been sent this week to other federal facilities, said Donald Murphy, a spokesperson for the Bureau of Prisons, or BOP. The unspecified number who remained at the minimum security prison near Oakland were pending release or transfer to halfway houses, he said.

Members of the Senate Judiciary Committee sent a letter to the BOP expressing concern over claims of a chaotic transfer process during which inmates on buses and planes didn’t receive proper medical care and were reportedly subjected to “mistreatment, harassment, neglect, and abuse while in transit.”

Susan Beaty, a lawyer for inmates who blew the whistle on the conditions at the prison, said there were reports that during transport guards made abusive comments to the women, “labeling them as snitches, referring to the closure of Dublin.” In addition, the inmates were shackled at their wrists and ankles for the entirety of their long journeys, despite their minimum-security classification, and in some cases were denied water and trips to the bathroom, Beaty said.

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The BOP didn’t immediately respond to the senators’ letter, but Murphy said the bureau was addressing all the inmates’ needs with “compassion and respect” during the transfer process.

“The process involved careful planning and coordination to ensure the safe transfer of women to other facilities, with special attention given to their unique programming, medical, and mental health requirements,” he wrote in an email to The Associated Press. “We remain committed to helping each individual adjust to their new environment with the necessary care and support.”

A 2021 Associated Press investigation exposed a “rape club” culture at the prison where a pattern of abuse and mismanagement went back decades. The Bureau of Prisons repeatedly promised to improve the culture and environment — but the decision to shutter the facility represented an extraordinary acknowledgment that reform efforts failed.

Following the sudden announcement April 15 that FCI Dublin would be shut down, U.S. District Court Judge Yvonne Gonzalez Rogers ordered a case-by-case review of each inmate’s specific needs before the transfers began.

In response, the bureau filed court papers questioning the authority of the special master appointed by the judge on April 5 to oversee the prison, who was tasked with reviewing each woman’s status. Inmate advocates hoped the judge’s decision would slow the shutdown. But the bureau proceeded with the process anyway, saying in a court filing that “extensive resources and employee hours have already been invested in the move.”

Five Senate judiciary committee members on Wednesday asked Bureau of Prisons director Colette Peters to provide information on preparations to close the facility and guidance given “for the safe and humane release from custody or transfer of individuals to other BOP facilities.”

“Individuals in custody at FCI Dublin have long endured a toxic carceral culture marked by sexual assault, harassment, and medical neglect at the hands of BOP staff. And now, while subjected to the deprivations and indignities of a flawed and rushed closure and transfer protocol, women in custody are reporting hostility and retaliation from BOP employees who blame them for the facility’s closure. This is unacceptable,” said the letter signed by Democratic senators Cory Booker of New Jersey; Richard Durbin of Illinois; Jon Osoff of Georgia; and Alex Padilla and Laphonza Butler of California.

Beaty said some of her clients have reportedly been sent to facilities in Texas, Florida, Minnesota and West Virginia.

“These are women who’d been able to see their kids and their parents and loved ones with some regularity. Now they’re distraught because they’ve been ripped apart,” Beaty said.

Advocates had called for most inmates to be freed — not transferred — from FCI Dublin, which they said was not only plagued by sexual abuse but also has hazardous mold, asbestos and inadequate health care. They also worry that some of the safety concerns could persist at other women’s prisons.

Last August, eight FCI Dublin inmates sued the Bureau of Prisons, alleging the agency had failed to root out sexual abuse at the facility. Their lawyers have said the civil litigation will continue.