An alcohol addicted professor reunites with his best friends at a high school reunion, then woke up and can’t find their friend, then looks for their best friend who betrayed them and decide to kill their best friend before his wedding.

Since this is a Comedy, you can get away with something ridiculous in order to get revenge or a way to coverup.
"When a high school reunion stag party turns into murder, three buddies must … "

Take care.

The crime was murder. They became enemies by one of them was caught having sex with their girlfriend and the girlfriend cheated.

That is my question - what is the crime/betrayal? How did they go from best friends to enemies?