NEW : 18-year-old was `` a good soldier , '' grandfather says . Now , before he went in ( and joined the Army ) , he was in , he was in with a bad crowd . '' U.S. soldier arrested in connection with killing of Mexican drug cartel member . Score: 6 Other suspects are Ruben Rodriguez Dorado and Christopher Andrew Duran .
NEW : 18-year-old was `` a good soldier , '' grandfather says . U.S. soldier arrested in connection with killing of Mexican drug cartel member . Score: 6 Other suspects are Ruben Rodriguez Dorado and Christopher Andrew Duran .