paragraph: The film opens as Mary Murdock , a young student , leaves a lively party at a club in New Jersey one night .  She hits a bad bump driving home drunk on a dark road .  Later , hearing noises in the garage , she finds a bleeding man , mangled and impaled on her jeep's bumper .  Not calling 911 , she tries to help , but he suddenly attacks .  Panicked , she hits him with a golf club .  After , she buries his body in a shallow grave in the woods off Clover Rd. .  The next day , Mary covers up the crime ; she scrubs off the blood but does n't get the dent fixed .  Mary starts coming apart .  Irrational , she crashes on a tree to camouflage the small dent with a bigger .  Later the news reveals the missing man is kindergarten teacher Timothy Emser , bipolar and unstable when he vanished .  Strange things occur in Mary's house , making her feel toyed with by someone unseen ; she descends into paranoia .  It transpires that Rick , her boyfriend , gets involved in the cover up and goes to retrieve incriminatory evidence off the corpse , but is killed , replaced in Emser's grave .  It becomes clear Emser survived .  Unhinged , he returns to make Mary live through the same nightmare she inflicted on him .  He stalks Mary many ways .  The parrots squawk strange phrases , Which alert Mary .  At one point , she falls down the stairs , impaling a screw driver in her thigh .  Emser surprise attacks , biting and stabbing her , and she passes out .  In a reversal , when Mary revives , Emser has strapped her to the bumper with electric cords and Christmas lights and takes her on a sadistic , all-night `` revenge drive '' . 
question: Who gets killed while trying to help Mary cover up the crime after strange occurrences started happening in her house?
answer: Rick