The Mafia—true origins unknown. Similar to extended social family, members were related by home village and Sicilian nationality, took an oath, swearing under punishment of death to a code of silence; self-protection group initially. Outlaw Motorcycle Gangs—disorganized and unruly groups made up of disgruntled World War II veterans, tough-guy image perpetuated and membership increased along with the organization and sophistication of the groups. More rebellious than openly criminal. Prison Gangs—increase has been linked to Cooper v. Pate, Supreme Court decision giving prisoners the right to sue state officials in federal court, changing prison conditions. Gangs grew in a more liberal prison environment. Urban Street Gangs—corruption, violence, continuity, multiple enterprises, structure and involvement in legitimate businesses, sophistication, discipline, and bonding.