WASHINGTON — A United Nations official said he should be allowed an official visit to the U.S. to assess the detention situation for migrant children after the in-custody death of a 7-year-0ld Guatemalan girl.

Jakelin Caal Maquin died Dec. 8 at a hospital in El Paso, Texas, after being detained with her father near the Antelope Wells Port of Entry in New Mexico. The group of migrants waited eight hours before boarding a bus to the Lordsburg Border Patrol Station. Customs and Border Protection said the girl began vomiting on the bus, but she wasn’t able to receive treatment until the bus arrived an hour and 40 minutes later. She had a 105.7-degree fever.

“Border Patrol agents, including trained emergency medical technicians, did everything in their power to provide emergency medical assistance for Jakelin Caal Maquin immediately after her father notified the agents of her distress at a remote Forward Operating Base, 94 miles from the nearest Border Patrol Station,” CBP Commissioner Kevin K. McAleenan said afterward. “Border Patrol agents revived Jakelin twice before emergency responders arrived via air ambulance to continue medical care.”

Telemundo tracked down the girl’s family to a poor village in Guatemala’s northern Alta Verapaz region, where Jakelin’s mother speaks the Mayan language Q’eqchi. The father’s attorneys said Jakelin “had not suffered from a lack of water or food prior to approaching the border.”

Felipe González Morales of Chile, who was appointed special rapporteur on the human rights of migrants in June 2017 by the UN Human Rights Council, said American authorities “must ensure that an in-depth, independent investigation” of the girl’s death takes place.

“Access to justice for her relatives should be granted, including but not limited to having legal representation in the proceedings in a language they understand well,” he said Monday.

“Redress to her family should be provided and if any officials are found responsible they should be held accountable. The government should also address failings within the immigration system, and specifically within the [Border Patrol] to prevent similar situations,” he added.

González Morales said the U.S. needs to stop detaining children, either entering the country with their families or unaccompanied, because “as repeatedly stated by a series of UN human rights bodies, detention of children based on their migratory status is a violation of international law.”

González Morales has twice requested an invitation from the U.S. government for an official visit but said he has not received a reply. “Conducting an official visit to the country would allow me to get first-hand, direct information about the situation of migrant children, especially on those who are being held in detention,” he said. “It would also allow me to present my recommendations to the U.S. government to fulfill its international commitments to respect and protect the human rights of all migrants.”

The UN said the rapporteur has reached out to U.S. officials “several times recently to raise a range of issues” about treatment of migrants and immigration rhetoric.

Customs and Border Protection has ordered medical checks on children 10 and under in the agency’s custody since an 8-year-old Guatemalan boy died late on Christmas Eve.

Felipe Gómez Alonzo and his father, Agustin Gomez, had been in custody since Dec. 18. The boy was taken to a hospital Monday morning with a cough and glazed-over eyes, was diagnosed with a cold and released back to CBP custody with a 103-degree fever. Agents decided to return the boy to the hospital at 10 p.m., and he died at 11:48 p.m.

Homeland Security Secretary Kirstjen Nielsen said in a statement today that “this tragedy, the death of a child in government custody, is deeply concerning and heartbreaking.”

“Smugglers, traffickers, and their own parents put these minors at risk by embarking on the dangerous and arduous journey north,” Nielsen said. “This crisis is exacerbated by the increase in persons who are entering our custody suffering from severe respiratory illnesses or exhibit some other illness upon apprehension. Given the remote locations of their illegal crossing and the lack of resources, it is even more difficult for our personnel to be first responders.”

Nielsen said she has asked the U.S. Coast Guard Medical Corps “to provide an assessment of CBP’s medical programs and make appropriate recommendations for improvements.”