This certainly does not seem like a typical part of PTSD. I would be interested to find out if the anti-social behavior might possibly pre-date the trauma and now be aggravated or triggered by stress. I would start with careful monitoring of the precipitants (including thoughts and feelings) that occur before the problem behavior. The literature on impulse control problems and anti-social behavior as well as anti-social personality disorder might be helpful. Chapters on Cognitive Therapy with anti-social personality disorder appear in "Clinical Applications of Cognitive Therapy" by Freeman, Pretzer, Fleming and Simon as well as in Beck's book "Cognitive Therapy with Personality Disorders". Good luck!