PHOENIX (AP) — A federal judge has sentenced a Mexican man to four years imprisonment for leading an illegal border crossing by migrants that resulted in a 16-year-old boy's death.

The U.S. Attorney's Office here said Wednesday that 24-year-old Omar Heriberto Robles-Hernandez earlier pleaded guilty in the case.

Robles-Hernandez had been the guide for six men and two teenage boys who crossed the desert from Mexico to enter the U.S. illegally.

The citizens of Mexico and Honduras were forced to carry backpacks of marijuana that each weighed about 50 pounds (23 kilograms).

Border agents found the group on May 23, 2017 after they had been in the desert 10 days. The 16-year-old boy was taken to the hospital, where he died from heat exposure and dehydration.