A 7-year-old girl has died while in the custody of the US Border Patrol. The girl crossed the U.S.-Mexico border with her father last week.  Federal immigration authorities confirmed the case, first reported by the Washington Post, on Thursday.

The Washington Post said the girl died of dehydration and shock more than eight hours after she was arrested by agents near Lordsburg, New Mexico. She was from Guatemala and was traveling with a group of 163 people who approached agents to turn themselves in on December 6. 

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It's unknown what happened to the girl during the eight hours before she started having seizures and was flown to a hospital in El Paso.

Processing 163 immigrants in one night could have posed challenges for the agency, whose detention facilities are meant to be temporary and are not made to hold that many people.

Inadequate facilities

When a Border Patrol agent arrests an individual, they get processed at a facility but usually spend no more than 72 hours in custody before they are either transferred to Immigration and Customs Enforcement or, if they are Mexican, quickly deported home.

The death of the young girl raises questions about whether border agents knew she was ill and whether she was given anything to eat and drink during the eight-plus hours she was in custody.

Immigrants, attorneys and activists have long raised concerns about the conditions of Border Patrol holding cells. In Tucson, an ongoing lawsuit claims holding cells are filthy, extremely cold and lack basic necessities such as blankets.

The Border Patrol reports it has seen an increasing trend of large groups of immigrants, many with young children, who walk up to agents and turn themselves in. Most are Central American and say they are fleeing violence.

Arresting such large groups create logistical problems for agents who have to wait on transport vans that are equipped with baby seats to take them to processing facilities, some which are at least half hour north of the border.

President Donald Trump has made tough immigration policies a central plank of his presidency, drawing fire from critics who accuse him of demonizing migrants for political gain.

av/msh (AFP, AP)

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