The Frighteners (1996) on Netflix

Frank Bannister is a man who goes around town claiming that he can talk with and see ghosts, though while he can, some believe (though he is, in fact) a common con-man who gets ghosts to make it appear though there is a haunting in whichever house is chosen, wherein he sweeps into action and pretends to remove the ghosts. All this goes on until one day strange deaths start occurring all throughout town and Frank ponders this, while his love interest, Lucy Lynskey, whose husband had only just died of the same cause, goes to the house of a deranged old woman who keeps her grown-up daughter locked up, saying that it is for the good of everyone else. Soon, it is revealed that even the ghosts themselves can see the force that is killing everyone off; a deceased mass murderer come back from Hell itself to continue killing. It is therefore up to Frank, Lucy, as well as two ghosts, to find out how to end the fiendish ghost from killing any more, while all the while trying to shake off a deranged detective from arresting them both.