If he’s a resident alien, he’s still eligible for assistance form his country’s embassy, and (most likely) Mexico will throw a stink up about the death penalty.
If it had been Mexico, of course, they would have just shot him and saved everyone the trial and trouble.
A crook in Mexico would be an idiot to stay there.
Come to America. More fat chickens to pluck and jails that are world class resorts compared to Mexico.