Why did walter reckless believe that there were "good boys in bad neighborhoods?"?

Walter Reckless (1899-1988) was an American criminologist, who developed the containment theory on delinquency and crime to explain the phenomenon mentioned above: why there are "good boys in bad neighborhoods".

This theory highlights how certain personal characteristics can isolate individuals from a surrounding environment full of delinquency. This person develops containment mechanisms, even tough, there are multiple stimulus around which push his/her towards crime. These mechanisms can be internal, such as a solid personality, clear goals in life, know how to manage frustation or external such as social groups which foster positive attitudes.

On the other hand, there are also opposite mechanisms, both internal and external as well, which bring individuals closer to crime.