Pocketknife Killer or Vulnerable Vacationer?

Overview

A day out on the river with friends ends in a deadly encounter, when a man stabs five people with a pocket knife, following a terrifying confrontation. The Defense argues the man believed his life was in danger and he acted in self-defense. With the entire incident recorded on cellphone, the Prosecution believes the man was the aggressor and this was intentional homicide. Is he a pocket knife killer or a vulnerable vacationer?