<P> Julie finds an article mentioning Susie 's father , Ben Willis , and realizes it is Ben they ran over , moments after he had killed David to avenge his daughter . She then goes to the docks to tell Ray , but he refuses to believe her . Julie notices Ray 's boat is called Billy Blue and runs away before Ray can explain that he went to see Missy to relieve his conscience . Ben appears , knocks Ray out , and invites Julie to hide on his boat . Looking around , she finds photos and articles about her friends and her , and pictures of Susie . Ben 's boat leaves the docks , as Ray regains consciousness and steals a motorboat to rescue Julie , who is being chased all around Ben 's boat . Ray ultimately uses the rigging to sever Ben 's hook - carrying hand and send him overboard . When the police question them , they deny knowing why Ben attempted to kill them , but they are relieved not to have actually killed anybody the previous summer , and reconcile . </P>
who was the killer in the movie i know what you did last summer
Ben Willis