It's no secret that the trademark of the Defias Gang is their Red Bandanas. But we've learned that the material from which these bandanas are made signifies the member's rank.
That being said, I want you to eliminate as many high ranking Defias members as you can. The highest ranking members will undoubtedly be found in VanCleef's secret hideout. When you're done bring me 10 Red Silk Bandanas as proof of their deaths and I will reward you. Good luck, <name>.