Parenti initially plans to target 18-21 year olds as this is the age group when violent behaviour is most commonly exhibited. He is known to the West Baltimore church deacon who puts him in touch with retired police officer Howard Colvin. Parenti is interested in meeting Colvin because he is well known around campus for his last action in the police department – a program of drug tolerant zones that significantly reduced crime in his district. Colvin takes a salaried position to assist Parenti with his study. Colvin convinces Parenti to target younger age groups by showing him that violent behaviour is entrenched in 18-21 year olds through a visit to his old district.