A small team of Venezuelans and former U.S. officials with deep connections to police and intelligence in the South American country has been providing information to the Trump administration about the number and identities of members of Tren de Aragua and other Venezuelan gangs headed to or already in the United States.

Tren de Aragua was originally a prison gang that Hector Guerrero Flores turned into a "transnational criminal organisation", according the US state department, which is offering a reward of $5m for information that could lead to his arrest. Guerrero Flores, 41, was in and out of Tocorón for more than a decade.