What is a person to make of those who refuse to hold the criminal elements of their society accountable?

Especially when their doing so harms innocent people.  Recall  23-year-old Ukrainian refugee Iryna Zarutska who was fatally stabbed on a light rail train in Charlotte, North Carolina.  

The perpetrator  Decarlos Brown, 34, was arrested shortly after the unprovoked attack and has been charged with murder. This person had been arrested and released 7 times before.

I am of the opinion that those responsible for his releases are guilty of a crime as well.