188. Not preventing evil from taking place is also a crime. 

There were three types of people in the previous times, those that committed evil acts, and those that held back people doing evil acts and those that did not stop people committing evil. Of these, Allah saved and protected only the ones who prevented people from committing evil acts, says verse (7:165) of the Quran.

Those who do not attempt to stop people committing evil and those who committed evil were destroyed altogether. 

Those that live without preventing people from committing evil cannot earn the good books of Almighty. This can be understood from this verse of the Quran.