from Breitbart:
Authorities in Mexico discovered a small narco-camp on an island from where Los Zetas fired on U.S. agents. The discovery came when Mexican state police forces raided the island one day after the initial shooting.
The raid took place on Tuesday when officers with the Tamaulipas State Guard made their way onto an island located on the Mexican side of the Rio Grande. It was from that island that on Monday, a group of at least four gunmen suspected of being part of the Cartel Del Noreste faction of Los Zetas fired at U.S. Border Patrol agents who were moving to intercept a group of migrants that had just crossed the river, Breitbart Texas reported.