The daughter of Eusebio Gonzalez, a policeman who was shot Tuesday while trying to stop a group of assailants, cries during a tribute to her father as she stands next to a folded Mexican flag in Ecatepec, Jan. 30, 2013.

The government of Mexico state -- the state that surrounds Mexico City -- has started a joint security operation with the Mexican army and federal police in areas of the Mexican state with high rates of violence, where more than 80 murders have been reported in January.