... but you found out in the past they hit their former boss after losing their temper and went to jail for 45 days because of it.... not yet knowing the rest of the story (because I don't know it yet, so I really can't fill you in here)...
Would you be judgemental and automatically assume you should forget this situation? Once a hitter, always a hitter and who know if he could hit you?
Would you wait until you find out the situation and determine from there? Maybe there was a good reason for what happened, he could have just gotten into a really bad situation and you may have done the same had it been you?
Or assume they paid their price to society, they don't have any other hitting in their past that you know of (this person would have told you that or your neighbor would), so why not just go for it?