WASHINGTON, July 25 -- The U.S. Department of Homeland Security's Immigration and Customs Enforcement issued the following news release: * * * Salvadoran serial criminal convicted of unlawful reentry after ICE Boston arrest * BOSTON -- A U.S. Immigration and Customs Enforcement operation resulted in a federal conviction for an illegally present Salvadoran national who unlawfully reentered the United States after having previously been deported. Arsenio Valladares, 44, pleaded guilty to one c  more