Can ex-employer sue you for time spent on the internet

I gave a 12 week notice with hopes of training my replacement so my leaving wouldn't disrupt work. After I gave my notice, my boss (the controller) gave his notice. He told me that he would not look for my replacement and would let his replacement find my replacement. It began to get closer to my quit date and was obvious that a replacement would not be here before I left. So I asked if I could cut my notice short by two weeks. The president called me into his office and told me that he didn't want me to leave regardless but would appreciate it if I stayed until my original notice date. He told me to go home and think about it. I did and decided that I would rather be home with my daughter. (I was quitting to go back to school to get a teaching certificate). The president wasn't around the next day (my last day) so I could not tell him personally, but the controller did. The following Monday when he did come, he went into the accounting dept and began to dog me to my co-workers and subordinates. He told them that I was unprofessional in the way I left and that my work was behind (which it was a little b/c we just finished having auditors at our company and having to put our work aside to be at their beck and call) and that I fool around on the internet (which I would, just like everyone else). He told everyone in our office that he is going to do everything in his power to make my life a living hell.

I'm going over so many scenarios of what he can do. Can he withhold my last paycheck? Can he sue me for wages for time I surfed the net? What can he do, really? By the way, I'm in Louisiana.