You need to be vigilant about the people she hangs out with. If some of her friends are constantly sharing these gangbanger stories, it might be time to encourage her to expand her social circle. At the same time, you can create a positive home environment. Fill your home with positive books, music, and art. When she is in such a positive environment, she will be less likely to be interested in those unwholesome stories.
Limit her exposure to media sources that might contain such stories. For example, be careful about the TV shows she watches or the websites she visits. You can set up parental controls on the devices if needed. Also, encourage her to engage in other activities like fitness or cooking which are more positive and less likely to involve such negative content.