MEXICO CITY (AP) — The Mexican military says it has detained the principle lieutenant in the Arellano Felix cartel that controlled drug trafficking in Tijuana for two decades.

Army spokesman Col. Ricardo Trevilla says 34-year-old Juan Francisco Sillas Rocha was captured in the border city across from San Diego, California.

He said Monday that Sillas allegedly reported directly to Fernando Sanchez Arellano, a nephew of the original Arellano Felix brothers who now runs the gang. Trevilla said Sillas was supposed to take on the Sinaloa Cartel in 2008, when Mexico's most powerful cartel stepped up efforts to take over Tijuana routes.

That battle is partly to blame for the spike in Tijuana violence between 2007 and 2009.