It can be done by machine if you are squeamish..
The killers right to life is lost when they take their victims lives in my book. They showed no mercy to their victims as they begged and pleaded for their lives. They have a right to a fair trial, but if convicted have lost their right to life, I think 12 months should be more than enough for appeals / new evidence etc. If the defense cant come up with any thing working 24/7 for those 12 months then time's up. Reasonable doubt will weed out poor cases.
I'm not talking crimes of passion etc here, but stranger killing, random deliberate killing for whatever reason.
One could argue that psychopathy is a mental disorder as they tend to have different brain structures, but then one could go that route about paedophiles etc etc. Maybe serial killers and child abusers should have special rights to equality and "understanding"?
I dont think so. Society is better off without them.