Late one Saturday evening , and Mark decide to a local. convenience store Mark has a loaded shotgun for the robbery , but both men agree beforehand that the shotgun is only to "scare " the cashier into giving up the money . During the robbery , however , the cashier unexpectedly out a handgun and points it at the two men .Mark panics , the trigger on the shotgun , and kills the cashier . is being charged as an accomplice to both robbery and murder . is an accomplice to mur der ? Why or why not ?