I'm in high school and very new to dungeons and dragons so I have no experience with this. I joined a new group recently made up of 3 mildly experienced players and a relatively new DM. 

Our DM decided to try Mines of Phandelver but it got horribly derailed. It was going good until I missed one meeting and one of the other PC's decided to go murder hobo, burn down the Inn in the first town, and use oil to try and kill as many civillians as possible. After this, the DM missed two meeting without telling anyone (with all the players showing up). After he came back, he made it so that the entire party appeared as criminals despite no one else doing anything. He's also not pulling his punches trying to kill the murder hobo through combat. 

The DM isn't saying anything about this but I'm worried that it's going to get out of control. Should I try to talk to the DM or PC about this or should I let it play out?