Admitting to the crime
In the notebook, he admits to the crime he committed against Gabby. He killed Gabby with his own hands.

Brian wrote: “I ended her life. I thought it was kind, and since she desired it, I assumed it was what she wanted. But now that I look at all my mistakes, I understand how wrong I was. “I was in a state of emergency. I was stunned. But from the second I decided to relieve her suffering, I knew I couldn’t live without her.”