Can you help me with the name of this movie (details inside)

Here’s the plot as I remember it (it’s a horror movie): there is a man whose wife gave birth to a boy. The boy looks like your run-on-the-mill child, nothing seems odd about him. One day, a priest meets the man, telling him that the boy is actually destined to be some kind of devil. The man doesn’t believe it and walks away, only to discover some time later that the priest is mysteriously killed. Then the wife has some accident and has to be admitted to the hospital. There is an old woman in the house (possibly a maid) who is very close to the boy. Soon after the wife gets to hospital, she goes there and kills the wife. The man begins to reconsider what the priest says and ask a friend for help. But then the friend is also killed. The man finds out that the boy is really a devil, and his real son was killed when he was unborn and replaced by the devil boy. The man gets back to get the boy and drive him to a church. When he attempts to kill the boy, he is shot by a policewoman.

Do you know which movie I am talking about?