So what I can remember is that the main character was a twin, but as a child her sister was murdered by the babysitters friend. He strangled her I think. The main character killed him, I am pretty sure she shot him and then ran away. The babysitter and the rest of the friends bury the twin and the killer in either a sinkhole or mud? I remember a door with a rose on it (I think it was stained glass). Pretty sure it’s a Canadian film if that helps. Also I think the main character goes back to that house when she’s grown up (I think she’s a cop?) and has forgotten she was a twin, and I think some haunting stuff goes on and she thinks it’s the little girl until the end when we find out it’s the babysitters friend who is the bad spirit? I really hope that is enough, it’s been driving me crazy not being able to find this movie.
The Marsh (2006) has haunting and a stained glass window with a rose.
https://www.youtube.com/watch?v=QZ5c1hMVZ7w&t=48s
https://www.imdb.com/title/tt0496350/