NEW : Two of the arrested were responsible for shooting ; they acted as lookouts , official says . Four family members of 3rd Petty Officer Carlos Angulo Cordova were killed . Tabasco attorney general said slayings were an act of revenge carried out by Los Zetas . He was killed in the shootout that resulted in the death of Arturo Beltran Leyva .
NEW : Two of the arrested were responsible for payout ; two acted as lookouts , official says . Four family members of 3rd Petty Officer Melquisedet Angulo 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 Arturo Beltran Leyva .