The Perfect Alibi? Stealing Dreams

I invented a consciousness exchanger and swapped bodies with death row prisoners to commit crimes every night. When I returned in the morning, the death row inmate woke up in prison with my memory, but convinced of his innocence. For ten years, I committed countless perfect crimes and got away with it. Until I woke up this morning and found myself still on death row. The prison guard sneered: "Congratulations, you are finally awake - this is your original body." "That 'you' chose to stay in your life ten years ago."