Dangerous Charm 1979 Directed by Chana Kraprayoon ไร้เสน่หา
An emotionally unstable spinster still hasn't gotten over the fact that her sister married the man she loved years ago. When her niece brings a new boyfriend home, memories of the past drive her to the brink of madness and she starts resorting to vicious, violent behavior (including murder) to ruin the relationship.
