http://www.apa.org/monitor/2014/02/criminal-mind.aspx

When people speak of criminals they think are they are just evil or psycho. But really a large percent of criminals have a biological factor that can back up why they did what they did. The brain is very complex but what researchers from many university's have found that the Amygdala which is in control of emotion and aggression. What they found was that a team of 26 year old men who had a lower amygdala volume has higher percent's of crime records, aggression, and violence versus those who have a higher volume. What they are looking at is just because it is the biological factor does that mean that they cant change it? Researchers went to a prison and did tests on inmates with various things such as just giving more vitamins and providing a more healthy life style to one group and placebo effect to the other and watches to see if their violence behavior changed at all. Those who were given a more healthy life style at the time, reduced their record for violence and penalties, while the other group remained steady with theirs. Another group was also put through a yoga class to find their inner peace and deal with their anger and stress and their violence reduced as well. Researchers believe that by giving someone with high anger and violence issues a healthier life style that they weren't given to begin with can actually help reduce their problems so they don't continue to behave in the way they have. Although other people may have more serious conditions such as tumors, malformations, and even drug issues. There are possible ways to prevent a criminal from lashing out more.
http://www.biologicalpsychiatryjournal.com/action/showFullTextImages?pii=S0006-3223%2813%2900312-0