CSI: NY S07 E04 Sangre Por Sangre

"How long does it take to get hooked on the latest CSI: hit? About a New York minute."

When the leader of a powerful New York gang, El Puño, is found murdered, the CSIs must find the killer before a street war with a rival gang breaks out. Mac asks the co-founder of El Puño, Luther Devarro, a man he put behind bars years before, for help.