From wikipedia: Blood sets on the East Coast are often seen as affiliated with the United Blood Nation, a gang which originated in Rikers Island. The United Blood Nation, simply called the Bloods, formed in 1993, within the New York City jail system on Rikers Island’s GMDC (George Mochen Detention Center), sometimes called C 73. GMDC was used to segregate problem inmates from the rest of the detention center. Prior to this time period, the Latin Kings were the most prevalent and organized gang in the NYC jail system.
From The Guardian today here. This article discusses how ISIL was formed in Camp Bucca, a US “prison” in Iraq.
I found the parallel disturbing, my first thought echoed Dostoyevski: The degree of civilization in a society can be judged by entering its prisons.