 After the arrest or assassination of various members of the Arellano Félix clan, the cartel is currently headed by Luis Fernando Sánchez Arellano, a nephew of the Arellano Félix brothers.The Gulf Cartel (Cartel del Golfo), based in Matamoros, Tamaulipas, has been one of Mexico's two dominant cartels in recent years.In the late 1990s, it hired a private mercenary army (an enforcer group now called Los Zetas), which in 2006 stepped up as a partner but, in February 2010, their partnership was dissolved and both groups engaged in widespread violence across several border cities of Tamaulipas state, turning several border towns into "ghost towns".