NEW : 18-year-old was `` a good soldier , '' grandfather says . U.S. soldier arrested in connection with killing of Mexican drug cartel member . Christopher Andrew Duran , 18 , was three of one men arrested 18 . Other suspects are Christopher Andrew Duran 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 . Michael Jackson Apodaca , 18 , was one of three men arrested Monday . Other suspects are Ruben Rodriguez Dorado and Christopher Andrew Duran .