Wed, 06 Feb 2013 10:13 UTC
Bremen scientist Dr Gerhard Roth says the 'evil patch' lies in the brain's central lobe and shows up as a dark mass on X-rays.
He discovered it when investigating violent convicted offenders over the years for German government studies.
We showed these people short films and measured their brain waves,' he said.
'Whenever there were brutal and squalid scenes the subjects showed no emotions. In the areas of the brain where we create compassion and sorrow, nothing happened.'
The dark mass at the front of the brain, he says, appears in all scans of people with records for criminal violence.
He added: 'When you look at the brain scans of hardened criminals, there are almost always severe shortcomings in the lower forehead part of the brain.
'There are cases where someone becomes criminal as a result of a tumour or an injury in that area, and after an operation to remove the tumour, that person was completely normal again.
'Or there are physiological deficits, because certain substances such as serotonin in the forebrain are not working effectively.
'But this is definitely the region of the brain where evil is formed and where it lurks.
'Of course it is not automatic. The brain can compensate somewhat for violent tendencies and it is unclear how that works.
'But when I will look at young people, and I see there are developmental disorders in the lower forehead brain, I can say that there is a felon in the making with 66 per cent probability.
'It is easy to spot this anti-social behaviour from very early on.'
Dr Roth said no two criminals are alike. He divides them into three groups for the purposes of his hunt for evil.
The first he classifies as 'psychologically healthy,' people who grow up in an environment where it is 'OK to beat, steal and murder'.
The second type is the mentally disturbed criminal who looks at his world as threatening.
'A wrong look, one false move, he can explode and become a killer,' he said.
The third group are pure psycopaths, a group in which tyrants such as Hitler and Stalin belong.
He said not all monsters are born and that many are made worse by their environments on their roads to evil.
He added: 'Experts detect a mental decline in some people that begins in the kindergarten. It is the task of society to offer widespread support to the children and their parents before they become criminals.'
Dr Roth is one of Germany's best-known brain specialists and has was at the forefront of calling for sentencing reforms a few years ago.