LOS ANGELES — Long before he ever traveled to the Persian Gulf, Marine Lance Cpl. Jose Gutierrez was acquainted with perilous and uncertain journeys. Lanky, quiet and full of ambition, Gutierrez, 22, is believed to be the second U.S. serviceman to die in combat, an American Marine with a distinctive Southern California background: He was among thousands of Central American immigrants who for years have made their way north in dangerous personal odysseys. At age 16, he had traveled by himself from his home in Guatemala, making his way across Mexico into the United States, where he was taken in...