FLAGSTAFF, Ariz. – A teenager is in custody and two men are being sought after a fatal gang-related fight in Flagstaff early Sunday morning.Flagstaff police said the fight near Elden Street and Brannen Avenue was between rival gangs retaliating against each other for a prior incident.Juan Hernandez, 23, of Flagstaff, died from stab wounds. Two other people were treated at Flagstaff Medical Center and are expected to recover from their injuries.A 17-year-old boy was arrested Sunday night. Police are looking for two 21-year-old "persons of interest." Police identified them as Michael Vallejos, aka "Buddy," and Jeremiah Barlow, aka "James."Anyone with information about this crime is asked to contact the Flagstaff Police Department at 928-774-1414 or Silent Witness at 928-774-6111. A reward of up to $2,000 is being offered in the case.