Having lived a while in Texas, I do believe that if Texans said not guilty because of insanity, then they must have felt really strongly that it was, cause Texans, as a rule are hard nosed about this sort of thing, even in cases where I felt differently about it. They don't lightly rule like this. It's not part of the Texan view of justice.
Must be a Houston thing because here in Dallas they sentenced Darlene Routier to death for killing her kids.
Is there a Guilty but Insane finding/choice in Texas?
I don't know the makeup of this jury but in my opinion they most likely blew the decision. True the prosecutor didn't asked for the death penality but the insanity plea is a very hard one to succeed with in Texas.
To deliberate for three days indicates to me that the jury most likely was hung at first and the insanity group finally convinced some of the others to change to the insanity verdict. We'll know more as they begin to talk.