I don't think the department would've taken the risk of suspending him if they didn't believe they had an airtight cause to fire him. Not sure about Minnesota employment law, but if it's like it is on most of the east coast, anyone can be fired at any time with "no reason given". And you have no legal recourse. They call this a "Right to Work" state, which is hilarious- should be "Right to Terminate Indiscriminately" states.