In some cases ex-prisoners commit crimes even after being freed from jail. Mostly Corrupt police and prison environment is the main cause behind it.
In many countries in America and Europe reported that the criminals do bad activities even after release form prison and they didn’t learn from their past, however, in my opinion the main cause is the homicidal prison behavior because mostly prison have bad environment t and even a small thief became a mentally exhausted monster after jail. In many countries murder is quite normal in their prison so mostly prisoners force to do such type of activates to secure themselves, and after their relies they continue same activities in their daily life even more worse.
On the other hand, European countries known for their better prison environment compared to USA. Even Denmark and Norway have prisons like a hotel room and have every kind of positive activities for prisoner for learning and entertainment.
They believe that positivity and gentleness make prisoners brain refresh and make positive effect on their brain. And it is internationally proven that European countries have less crime activities of prisoner’s compared to USA. Moreover, changing the environment of prison and make it friendly and educational for prisoners can definitely resolved this issue.
In conclusion, criminal and homicide environment is the main cause behind ex-prisoners crimes, and it only solve with a nation-wide change in prison environment and giving resources to prisoners, for their positive behavior.