"I have directed the Texas Department of Public Safety and the Texas Rangers to work with local law enforcement to conduct a full investigation into this crime," the governor said in a statement posted on social media.
He also added that the Texas Office of Emergency Management has been tasked with providing local authorities with all the necessary resources "to respond to this tragedy."
According to the latest data, 19 children and three adults died in this tragedy, including the grandmother of the shooter, who died outside the school premises.