sentences:  Eric believes that Marsh never left the island and brought the couples there to kill them, a supposition that is granted some support when Marsh is later seen on the island.Kay believes that the island has allowed her dreams to cross over into reality, and that the creature from her nightmares is responsible—a theory supported by the fact that the deaths only occur when Kay is asleep.Additionally, it becomes apparent that Kay herself may be the killer, murdering in the throes of a somnambulistic trance out of repressed resentment towards her loved ones.