Looking for title

Hey guys! Need some help finding a manga again..
It is pretty new and quite psychological. it was about a very cheerful teacher who worries about a student because he isolates himself so much. He reminded her of how she used to be when she was a student. Later she finds out he is the son of her former teacher who used to blackmail and rape her during her school years..she was also abused by her stepfather and the teacher found out about it and shot a photo while she was forced...that's what he used to blackmail her into sleeping with him as well. That teacher now also abuses his stepson. Now she is planning to help him by killing his father / her former teacher.
Help very much appreciated!