If you are not worried about being caught, going to jail, societal isolation, the whole death penalty thing, anyone can moonlight as a forensic pathologist. I will take you on as a patient, but when you die, I get to have first dibs on doing your autopsy to see if I was right about that heart condition and the prostate tumor. That ought to go over well with patients. They would flock to you.
Seriously, I think that this is not a very realistic query. Seeing patients is a full time job. Forensics is a full time job. You can't really hope to be an expert on both and practice in each. I think once you start exploring the fields you will find which area is more appealing.
You can, however, moonlight as an autopsy diener (the one who opens the body and assists the pathologist). That might give you a lot of what you are looking for, Dr Lecter, while still being able to see patients in an office practice. Most dieners are not physicians, but then again that is probably because most physicians do not want to be dieners, as they pay is probably not so great. Go for it though. Moonlight.