The bodies of three small children and a woman were discovered Sunday by Border Patrol agents near the Rio Grande River in Texas, authorities said.
Hidalgo County Sheriff Eddie Guerra said two of the children were infants and one was a toddler. The woman was 20 years old.
The four bodies were found by the river southeast of Anzalduas Park in the Las Palomas Wildlife Management Area south of McAllen, Texas.
The area is popular for immigrants who cross into the US. Border Patrol agents in the Rio Grande sector apprehended 33,960 families in May, the most of any sector that month.
Because the bodies were on federal land, the FBI is investigating.
“It’s an incredibly heartbreaking situation, which seems to happen far too often,” said FBI Special Agent Michelle Lee.
There is no indication at this point of foul play, and it appears as though the woman and three children died from dehydration and heat exposure, a US official said. Although the victims haven’t been identified, it appears all four were undocumented immigrants.
Earlier in the day, Sheriff Guerra tweeted there was a dangerous heat advisory in effect from noon to 8 p.m., with temperatures in McAllen near where the bodies were found expected to be 113 degrees.