<P> Julie goes back to Missy, who reveals David allegedly committed suicide out of guilt for the death of his girlfriend Susie in the crash of the car David was driving . Missy shows David's suicide note to Julie . As the writing matches that of the note she received, Julie realizes it wasn't a suicide note but a death threat . At the Croaker Pageant, Helen witnesses Barry being murdered on the balcony . She rushes up there with a police officer but finds no sign of the killer or Barry . </P> <P> While driving Helen home, the officer is stopped by a stalled truck, then killed by a dark figure with a hook . Helen rushes to her family's store, but the killer follows her inside and kills Helen's sister Elsa . Helen manages to flee, but the killer chases her into an alley and slashes her to death, her screams drowned out by the noise of the parade . </P> <P> Julie finds an article mentioning Susie's father, Ben Willis, and realizes it's Ben they ran over, moments after he had killed David Egan to avenge his daughter . She then goes to the docks to tell Ray, who's skeptical . 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 shows up, knocks Ray out and invites Julie to hide on his boat . Looking around, she finds photos and articles about her and her friends, and pictures of Susie . Ben's boat leaves the docks, as Ray regains consciousness and steals a motorboat to rescue Julie, who's 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're relieved not to have actually killed anybody the previous summer, and reconcile . </P> <P> A year later, Julie is in college in Boston . As she enters the shower, she notices the words "I still know" on the mirror . Moments later, a dark figure crashes through it . </P>

Who was the murderer in i know what you did last summer