CARACAS, Venezuela (AP) — Debates over President Donald Trump’s hardline migration policies are focused on the Venezuelan gang Tren de Aragua, to some a ruthless transnational criminal organization and to others the pretext for an overhyped anti-migrant narrative.

The Trump administration has sparked controversy with its move Sunday to deport 261 people, some of whom it alleges are members of the Venezuelan gang Tren de Aragua, to an infamous maximum-security prison in El Salvador.

The Trump admninistration has invoked a 227 year old law, the Alien Enemies Act, to target Tren de Aragua, a gang with its roots in the prisons of Venezuela. Who are they and how wide is their reach?