'It's where evil lurks': Neurologist discovers 'dark patch' he believes exists in the brains of ALL murderers, rapists and violent criminals A leading German neurologist believes he has found an "evil patch" in the brains of violent criminals. Having spent years analysing the brains of convicted offenders for the German government, Dr Gerhard Roth now claims brain scans of rapists and murderers reveal a dark mass between the two frontal lobes. Speaking to the Daily Mail Dr Roth said: "We showed these people short films and measured their brain waves...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. According to Dr Roth, almost all hardened criminals have "severe shortcomings" in the part of the brain that sits in the lower forehead, leading him to believe that some offenders may have a "genetic predisposition" to violence. He also believes short-term medical problems in the same area of the brain can lead to criminal behaviour. Dr Roth said: "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." He added: "Of course it is not automatic. The brain can compensate somewhat for violent tendencies and it is unclear how that works... But this is definitely the region of the brain where evil is formed and where it lurks. Dr Roth, who is a leading voice in Germany's sentencing reform debate, believes the dark patch in the brain is so closely associated with violent crime that it could theoretically be used to spot and stop those inclined to violence long before they ever commit a crime. He says: "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 believes that criminal mental decline "begins in the kindergarten," but a positive parental environment and strong societal support can easily stop the child going on to offend. Equally, a negative domestic situation could easily lead to a child otherwise moderately pre-disposed to violence, to become a hardened criminal.