A six-year-old girl from India died of heat stroke in an Arizona desert after her mother left her with other migrants to go in search of water, a medical examiner and U.S. Border Patrol said on Friday.

The girl, Gurupreet Kaur, soon to celebrate her seventh birthday, was found by U.S. Border Patrol west of Lukeville, Arizona on Wednesday, when temperatures reached a high of 108 degrees Fahrenheit (42 Celsius), U.S. Border Patrol and the Pima County Office of the Medical Examiner (PCOME) said.

The girl’s death, the second recorded fatality of a migrant child this year in Arizona’s southern deserts, highlighted the danger of summer heat as a surge of migrant families, mainly from Central America, cross the U.S.-Mexico border to seek asylum.

An increasing number of Indian nationals are entering the United States from Mexico, according to immigration officials. They are among thousands of Africans and Asian migrants making the arduous journey, led by smuggling cartels.

Human rights activist Juanita Molina said U.S. border security measures were also partly to blame, along with the exhausted state of Indian child migrants once they reach the border.

“They’re trying to unload people in places where they can avoid detection themselves,” Molina, director of Tucson-based Border Action Network, said of smugglers.

“For a young child, death can come very quickly,” she added.