Uncovering the Truth Behind Her Husband's Death

My name is Nuoyan, and I am a forensic doctor. When I took over the case of a female teacher who mysteriously fell from a building, I found a wedding ring in her stomach. Engraved on the inside: "To my eternal lover." The forensic department told me that this ring belonged to the scene where my husband died in a car accident three years ago. That day, a ring was also found next to his body, but it was engraved on the inside: "To my only promise." Now, surveillance shows the husband was in the school hallway last night. My scalpel is trembling.