How does Mexico handle illegal immigrants?
They murder them

This from Associated Press:

TUXTLA GUTIERREZ, Mexico – Mexican officials say gunmen have attacked a group of illegal immigrants in southern Mexico, killing one and wounding five as well as an alleged people smuggler.

According to Mexico's federal preventative police, gunmen fired on a truck carrying the migrants before dawn Saturday along a highway outside the city of Comitan in Chiapas state.

Federal officials say an Ecuadoran man was fatally shot and at least six others suffered wounds, including the suspected smuggler.

The officials say wounded immigrants told police they hired a smuggler to take them across Mexico so they could sneak into the United States.

Immigrants have been increasingly attacked in Mexico by gangs trying to extort money from their families.