CSI: NY (2004)

S07E04 Sangre Por Sangre

After the head of the notorious New York gang, El Puño, is discovered dead, the CSIs race against time to identify the murderer and prevent an impending gang war with a competing faction. Mac reaches out to Luther Devarro, the co-founder of El Puño and a man he locked up years ago, seeking his assistance in unraveling the case.