(NewsNation) — California authorities announced dozens of gang member arrests in connection with the cartel-style shootings last month dubbed the Goshen massacre. Authorities say the massacre was a result of conflict between two rival gangs.

Robert Monte, former U.S. Marshall and deputy chief of the El Paso, Texas, Police Department, joined “NewsNation Prime” to discuss Operation Nightmare, the investigation into these shootings.

“Make no mistake about it, the prison gang and the street gangs are working with the Mexican cartels, and they’ve been doing that for a while. So this investigation that began as a result of that massacre was intelligence-driven and several agencies were involved,” Monte said.

Watch Monte’s interview in the player above.