Three Democratic senators want answers from Immigration and Customs Enforcement about a transgender woman who died in the agency’s custody after seeking asylum in the United States.

Roxsana Hernández died in May due to dehydration and complications related to HIV, according to an independent autopsy, which also revealed evidence that she had likely been beaten and had “extensive deep hemorrhages” on her wrists “typical of handcuff injuries.”

In a letter to the Customs and Border Protection commissioner and acting director of ICE on Wednesday, Sens. Kamala Harris (D-CA), Tom Udall (D-NM) and Martin Heinrich (D-NM) echoed a criticism from activists — that ICE is withholding information about Hernández’s death.

“It is deeply troubling that ICE has been uncooperative in releasing information about Ms. Hernandez’s case,” the senators wrote. “This violates congressional requirements. Congress requires ICE to publish an initial report, for public release, on each in-custody death for within 30 days and similarly for a final report within 60 days. It has been over 180 days since Ms. Hernández was pronounced dead and no such report has been publicly released.” (Read the senators’ full letter below.)

Citing personnel at Lovelace Medical Center, ICE initially said Hernández’s preliminary cause of death was cardiac arrest. Later, responding to the independent autopsy, ICE denied that Hernández had been physically abused in custody.

Lawyers from the Transgender Law Center, one of the groups representing Hernández’s family, have filed a wrongful death tort claim in New Mexico.

Hernández traveled with a so-called “caravan” of Central American migrants and asylum seekers to the U.S. border. While traveling with the caravan, she told BuzzFeed News in an interview: “They kill trans people in Honduras. I’m scared of that.”

After being reportedly detained for five days in a Customs and Border Patrol facility known for its freezing cold temperatures, Hernández was transferred to ICE custody, eventually to Cibola County Correctional Center. That facility is owned and operated by the private prison company CoreCivic (formerly Corrections Corporation of America) under contract with ICE.

Read the senators’ letter below:

H/t BuzzFeed News.