NEW : Angulo Cordova 's brother was injured in the shooting and later died in a hospital . two of the arrested were responsible for payout ; Two acted as lookouts , official says . Four family members of CNN Officer Melquisedet Cordova were killed . Tabasco attorney general says slayings were an act of revenge carried out by Los Zetas . Cordova was killed in the shootout that resulted in the death of Angulo Cordova .
NEW : two of the arrested were responsible for payout ; Two acted as lookouts , official says . Four family members of CNN Officer Melquisedet Cordova were killed . Tabasco attorney general says slayings were an act of revenge carried out by Los Zetas . Cordova was killed in the shootout that resulted in the death of Angulo Cordova .