The Itchy & Scratchy Show:
Season:     3     / Episode:     4    
The Sounds of Silencers

After having a terrible day at school, Bart stumbles upon the "Legitimate Businessman's Social Club" Mafia bar where the leader, Fat Tony, hires him to work as their permanent bartender. However, when Principal Skinner ends up missing for nearly a week, Bart is immediately blamed for murdering him, causing Bart to get sent to court. As Bart is about to get convicted, the principal shows up which leads to Bart being cleared of all the charges.