The book the 4th star about a couple Generals of Iraq has their first hand accounts of having to go armed and in buddy teams into the Bs.
https://www.amazon.com/Fourth-Star-Generals-Struggle-Future/dp/0307409074
Gangs didn’t go away. There was a straight up gang fight on post in Baghdad circa the Surhe when the IL Guard couldn’t leave their gangster shit at home.