Was I wrongfully Discharged

I was told I was terminated for a violation of the employee conduct policy. I was a Supervisor, another Supervisor the same level as me logged on to a computer that I previously used and got into my personal files. I had a file in my personal file labeled "jokes", He found some things in my file that were deemed inappropriate and he informed upper management of what he had found. He did this because he was employed on third shift and I was employed on First shift so he figured if he told on me and got me in trouble he would have a better chance of getting to first shift. Upper management knew I had this "Joke" file because 2 months earlier they had sent out an email to all Supervisors telling us to delete anything from your computers that was not company related. I deleted everything from the computer I was using at the time and had no Idea the files would still be on the computer I used previously. When upper management sent out this email it showed a screen shot of my files and it also showed that I had a joke file. This is why I feel the company set me up to fail. This screen shot of my files showed all the Supervisors what I had in my files and gave this person the idea to get me in trouble. Management knew I had the files but did not act on this until another Supervisor went into my files. After the incident IT went in and blocked all access to any other profile other than your own. The other Supervisor is under no disciplinary action, but I was the one that got terminated even though management knew I had the file!