On this issue, I strongly disagree with Philip Nitschke.
Everyone ought to be accountable for their actions! If found guilty of a serious crime (i.e., homicide, rape, pedophilia, etc.), the loss of freedom is reasonable. Euthanasia is way too easy of a way out for criminality. There are reasons for prison time; it offers the felon the opportunity to suffer and reflect on the suffering they have caused to others. Perhaps, he/she can be rehabilitated; if not at the very least, an attempt was made.
I do want to mention that Dr. Nitschke is far too commercial, as he has employed compassionate publicity for personal financial gain. Frankly, I do not view him as a "true" medical doctor.