They’re really outing themselves now. They’re not even trying to pretend that they’re there as Hamlet’s friends. This line makes it crystal clear where their alliance lies.
1) They know about the dead body. And they’re coming after Hamlet for it.
2) They have the job of carrying the dead body to the chapel. This is not work you give your step-son’s friends. This is work you give to your cronies. Plain and simple. What’s that line about how a good friend will help you move but the best friends will help you move a body?