Johana Medina Leon, 25, died on Saturday at a hospital in El Paso, Texas, after being diagnosed as HIV-positive and complaining of chest pains, U.S. Immigration and Customs Enforcement (ICE) said.
Medina Leon, a trans woman from El Salvador, was taken into ICE custody in April and was held in detention at the Otero County Processing Center in New Mexico.
Late last month, she was admitted to hospital on the day that she was granted parole following a positive assessment of her asylum application, ICE officials said.
"This is yet another unfortunate example of an alien who enters the United States with an untreated, unscreened medical condition," Corey Price, a director for ICE enforcement and removal operations in El Paso said in a statement.
"Many of these aliens attempt to enter the United States with untreated or unknown diseases, which are not diagnosed until they are examined while in detention."
But LGBT+ and immigration advocates said Medina Leon's death was part of a wider pattern of mistreatment and poor medical care for migrants while in ICE custody.
In April, New Mexico officials released an autopsy report on the death of Roxsana Hernandez, a transgender woman from Honduras, who died while in ICE custody last year.
The report concluded that Hernandez died of an AIDS-related condition called multicentric Castleman disease.
"The death of a second transgender immigrant who was seeking asylum ... clearly tells us that ICE isn't equipped to meet the needs of transgender individuals," Emilio Vicente of Familia: Trans Queer Liberation Movement, a transgender rights group, told the Thomson Reuters Foundation.
"People who presented themselves at the border and were seeking a better future, and instead found death. That's the tragedy of all of this," he said.
Lawyers from the American Civil Liberties Union (ACLU) and other local migrant advocacy groups spent several weeks earlier this year interviewing gay and trans asylum seekers at the Otero facility.
In March they sent a letter to U.S immigration officials expressing "grave concerns" over detention conditions.
The letter claimed asylum seekers at the facility were sexually harassed, illegally kept in solitary confinement, and given "inadequate medical care."
"We had several conversations with transgender women and gay men who were detained (at Otero), who described horrific conditions including severe medical neglect," said Kristin Greer Love, a staff lawyer at the ACLU New Mexico.
"When people did make requests for medical treatment, it took ICE days and sometimes even weeks to respond to those requests, including urgent requests."
Andrew Lorenzen-Strait, deputy assistant director of custody management for ICE, told the Thomson Reuters Foundation last week, before news of Medina Leon's death broke, that the agency is committed to treating trans migrants respectfully, especially with regard to medical care.
"Members of our public health service are specialized in these infectious (diseases) to provide expert medical training to the staff that care for them directly," he said.
"I can tell you without a one shred of doubt that ICE takes very seriously the care and responsibility of this population."As of May 28, there were 112 self-identified transgender detainees in ICE custody being housed in 28 different facilities, according to the agency.