I remember watching this movie with my family when I was little. So it must be a 90’s movie, although could possibly be late 80’s.
I remember it was about a family that lived on a farm (horses) and I believe that they were fairly wealthy. (the head of the household was a famous painter) All these mysterious deaths kept occurring. In the end it turned out the character that did it was one of the family members. He would go out to a cabin to do his painting to be alone. But he was only painting his name over stolen paintings. He just did a painting himself of all the murders that he had done. It was really creepy looking and he wasn’t a good artist. I think he even killed a baby and buried someone over someone else’s grave.