Could you help me find a movie?

I saw this film a very very long time ago, so I don’t remember much of it. It was some sort of a horror movie.
The main character was a woman. I think she was a policewoman. She had a male companion.
It had a little girl in it. Ever since she became an orphan, she wouldn’t speak to anyone. The main character tried to speak to her to find out what happened, but she wouldn’t talk to her. I think the little girl had a brother. He and their mother died when their house burnt down. People thought that their mother went crazy, she hurt the little girl. Later it turned out that it was actually the brother who had hurt the girl, and the mother just wanted to protect her. I don’t remember what was wrong with the brother, but the film had some sort of a supernatural thing lurking in it.
I remember that the two investigators went to a hospital that also burnt down. The woman arrived there first. The man told her on the phone that she shouldn’t go inside alone. But of course, she decided to go inside anyway. Inside the hospital, the woman saw the mother’s corpse. The corpse started to move. Later it turned out that it just wanted to protect the woman… from her evil son’s ghost (?).
Later, the two main characters were in a room, when someone knocked on the door. The man looks out on the peephole, and he gets stabbed in the head through the peephole. He dies, and a black pearl falls out from his mouth. Actually, everyone who gets killed by this thing, has a black pearl falling out from their mouth. So, black pearls have some kind of importance in the story. Maybe the brother gave his sister pearls after every time he hurt her so that she wouldn’t tell their mother.
Unfortunately, that’s all I can remember. I would be so thankful if someone could tell me its title.