Galligan told Good Morning America last week that his client will probably plead not guilty and that an insanity defense is possible.
"I'm fairly confident that that's going to have to at least be examined," said Galligan. "And that's problematic. But we haven't reached that stage yet."
Galligan, a retired Army colonel, served as a defense attorney, prosecutor and judge during more than three decades in the military. He is now in private practice in Belton, Texas.