And that is why all four suspects are still alive./s
Harris County has the highest rate of death penalty convictions in the nation. These four will die, either at the hands of the state of Texas, or in the general prison population, executed by Zetas who do not want these guys to rat on them. They are dead men walking.
In the mean time, hopefully the state of Texas can use information from them to find the other Zetas and to trace the guns (”Fast and Furious”?).