The convict John Allen Rubio was earlier sentenced to death. However, a state appeals court overturned the verdict in 2007 as statements from the children's mother, Angela Camacho, were wrongly allowed as evidence.
Now, the prosecutors are yet again seeking death for the killer.
The guilt of Rubio was never even contested. The defence was only trying to beg mercy of the jury by placing an insanity plea. The defence attorneys used Rubio's troubled childhood, his mother's prenatal drinking, his stepfather's abuse, his experience as a teen prostitute to support their argument.
However, the insanity defence was shrugged off by the jury.
In his testimony, Rubio claimed that the children were possessed. He believed that he was the "chosen one" intended to save the world leading him to behead the 'demon' children.
"This kind of crime tears at the fiber of who we are here in the Valley," Cameron County District Attorney, Armando Villalobos said showing a photograph of a headless child and making a chopping motion on the floor with a cleaver, an international news agency reported.