A top operative of the Tijuana drug cartel was captured by army troops over the weekend, the Mexican Defense Secretariat said Monday.

Juan Francisco Sillas Rocha and three associates were arrested Saturday by 2nd Military Zone troops in Tijuana, a border city in the northwestern state of Baja California.

The 34-year-old Sillas Rocha, a native of Sinaloa state, was the No. 2 man in the criminal organization led by Fernando Sanchez Arellano.

Sillas Rocha is considered one of Mexico’s “most violent (drug traffickers), responsible for a great many murders,” the secretariat said.