It was an edict by Hsinbyumashin that ordered almost all possible heirs to the throne be killed .
Hsinbyumashin 's daughter Supayalat and son - in - law Thibaw would become queen and king .
It was an edict by Hsinbyumashin that ordered almost all possible heirs to the throne be killed , so that her daughter Supayalat and son - in - law Thibaw would become queen and king .