A relative of the dead boy who had been playing with him told the AP that the Mexicans — who he described as federal police, not soldiers — pointed their guns only when the Americans waded into the mud in an apparent attempt to cross into Mexico.

The Mexican authorities accused the Americans of trying to recover evidence from Mexican soil and threatened to kill them if they crossed the border, prompting both sides to draw their guns, said the 16-year-old boy who asked not to be further identified for fear of reprisal.