From our friends at KATC TV 3 :

Only one piece of evidence from Brandon Scott Lavergne's trial has been entered into evidence because it was the only evidence required when he pled guilty to murdering Mickey Shunick and Lisa Pate in August. A psychological evaluation was required before a plea deal would be accepted by prosecutors.

The evaluation was done on August 8, 2012 and outlines a history of depression, physical abuse, and molestation. More details are available here from KATC.