Je dois écrire une lettre a mon professeur en lui racontant une scène mystérieuse donc j'ai été témoin

You could say : yesterday, at 10pm, I heard a strange thing...this sound was next to the forest, so I went in the forest. I saw three girls with a frightening head. She had a long dresses, and a long brown hair. She had something strange in her hands. In front of her, there was a little boy crying. He looks like a vampire ! And the girls look like...a witch...I don't know why the little boy crying, but I'm sur this girls are mean...