FILE - U.S. Immigration and Customs Enforcement (ICE) agents enter an apartment complex looking for a specific undocumented immigrant convicted of a felony during an early morning operation in Dallas, Texas, March 6, 2015.
FILE - U.S. Immigration and Customs Enforcement (ICE) agents enter an apartment complex looking for a specific undocumented immigrant convicted of a felony during an early morning operation in Dallas, Texas, March 6, 2015.

An Indian man in U.S. immigration custody died in an Arizona jail last week, federal officials announced late Monday. 

Simratpal Singh, 21, was found unresponsive on May 2 at La Paz (Arizona) County Jail, where he was awaiting transfer to a U.S. Immigration and Customs Enforcement facility, the agency said in a statement

Medics transported him by ambulance to a local hospital, then by helicopter to a second facility, where personnel declared him dead shortly before 2 a.m. on May 3.

Singh was initially arrested on charges of assault and sexual assault. 

He posted bond before being released into ICE custody.

An autopsy is pending to determine the official cause of death, according to ICE.

Singh is the fifth detainee to die in ICE custody in fiscal 2019. The agency sees about 10 deaths in its custody every year. 

The medical treatment of people held by ICE and U.S. Customs and Border Protection is under heightened scrutiny as the Trump administration continues a series of policy decisions designed to limit immigration while responding to an increased number of families arriving at the southwest border. 

Immigrant advocates question the speed and quality of care that those in custody are receiving.

FILE - A U.S. Border Patrol truck sits at the U.S.-Mexico border in El Paso, Texas.

Days before Singh's death, a 16-year-old Guatemalan boy who crossed into the U.S. without his parents died while in the care of the U.S. Department of Health and Human Services, the agency tasked with caring for unaccompanied children who enter the country without legal status.

Mental health researchers have also raised concerns and linked immigration detentions to "severe mental health consequences." 

No other information about the circumstances of Singh's death, or of the criminal charges against him, was immediately available Tuesday.